{"id":1634,"date":"2022-11-22T18:54:51","date_gmt":"2022-11-22T10:54:51","guid":{"rendered":"https:\/\/qaqaq.top\/?p=1634"},"modified":"2022-11-27T12:40:57","modified_gmt":"2022-11-27T04:40:57","slug":"%e6%95%b0%e6%8d%ae%e5%87%86%e5%a4%87%e4%b8%8e%e7%b4%a2%e5%bc%95%e5%a4%b1%e6%95%88%e7%9a%8411%e7%a7%8d%e6%83%85%e5%86%b51%e3%80%81%e7%b4%a2%e5%bc%95%e5%a4%b1%e6%95%88%e7%9a%8411%e7%a7%8d%e6%83%85","status":"publish","type":"post","link":"https:\/\/qaqaq.top\/?p=1634","title":{"rendered":"\u6570\u636e\u51c6\u5907\u4e0e\u7d22\u5f15\u5931\u6548\u768411\u79cd\u60c5\u51b51\u3001\u7d22\u5f15\u5931\u6548\u768411\u79cd\u60c5\u51b52\u3001\u5916\u8fde\u63a5\u4e0e\u5185\u8fde\u63a5\u7684\u67e5\u8be2\u4f18\u5316\u3001JOIN\u8bed\u53e5\u7684\u5e95\u5c42\u539f\u7406\u3001\u5b50\u67e5\u8be2\u4f18\u5316\u4e0e\u6392\u5e8f\u4f18\u5316\u3001GROUP BY\u4f18\u5316\u3001\u5206\u9875\u67e5\u8be2\u4f18\u5316\u3001\u8986\u76d6\u7d22\u5f15\u7684\u4f7f\u7528\u3001\u7d22\u5f15\u6761\u4ef6\u4e0b\u63a8(ICP)\u3001\u5176\u4ed6\u67e5\u8be2\u4f18\u5316\u7b56\u7565\u3001\u6dd8\u5b9d\u6570\u636e\u5e93\u7684\u4e3b\u952e\u5982\u4f55\u8bbe\u8ba1"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code># \u7b2c10\u7ae0_\u7d22\u5f15\u4f18\u5316\u4e0e\u67e5\u8be2\u4f18\u5316\r\n\r\n# 06-\u7d22\u5f15\u4f18\u5316\u4e0e\u67e5\u8be2\u4f18\u5316\r\n\r\n# 1. \u6570\u636e\u51c6\u5907\r\n\r\nCREATE DATABASE atguigudb2;\r\n\r\nUSE atguigudb2;\r\n\r\n# \u6b65\u9aa41\uff1a\u5efa\u8868\r\nCREATE TABLE `class` (\r\n    `id` INT(11) NOT NULL AUTO_INCREMENT,\r\n    `className` VARCHAR(30) DEFAULT NULL,\r\n    `address` VARCHAR(40) DEFAULT NULL,\r\n    `monitor` INT NULL,\r\n    PRIMARY KEY (`id`)\r\n) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;\r\n\r\nCREATE TABLE `student` (\r\n    `id` INT(11) NOT NULL AUTO_INCREMENT,\r\n    `stuno` INT NOT NULL,\r\n    `name` VARCHAR(20) DEFAULT NULL,\r\n    `age` INT(3) DEFAULT NULL,\r\n    `classId` INT(11) DEFAULT NULL,\r\n    PRIMARY KEY (`id`)\r\n    #CONSTRAINT `fk_class_id` FOREIGN KEY (`classId`) REFERENCES `t_class` (`id`)\r\n) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;\r\n\r\n# \u6b65\u9aa42\uff1a\u8bbe\u7f6e\u53c2\u6570\r\nSET GLOBAL log_bin_trust_function_creators=1; # \u4e0d\u52a0global\u53ea\u662f\u5f53\u524d\u7a97\u53e3\u6709\u6548\u3002\r\n\r\n# \u6b65\u9aa43\uff1a\u521b\u5efa\u51fd\u6570\r\n#\u968f\u673a\u4ea7\u751f\u5b57\u7b26\u4e32\r\nDELIMITER \/\/\r\nCREATE FUNCTION rand_string(n INT) RETURNS VARCHAR(255)\r\nBEGIN\r\n    DECLARE chars_str VARCHAR(100) DEFAULT\r\n    'abcdefghijklmnopqrstuvwxyzABCDEFJHIJKLMNOPQRSTUVWXYZ';\r\n    DECLARE return_str VARCHAR(255) DEFAULT '';\r\n    DECLARE i INT DEFAULT 0;\r\n    WHILE i &lt; n DO\r\n        SET return_str =CONCAT(return_str,SUBSTRING(chars_str,FLOOR(1+RAND()*52),1));\r\n        SET i = i + 1;\r\n    END WHILE;\r\n    RETURN return_str;\r\nEND \/\/\r\nDELIMITER ;\r\n#\u5047\u5982\u8981\u5220\u9664\r\n#drop function rand_string;\r\n\r\n# \u968f\u673a\u4ea7\u751f\u73ed\u7ea7\u7f16\u53f7\r\n#\u7528\u4e8e\u968f\u673a\u4ea7\u751f\u591a\u5c11\u5230\u591a\u5c11\u7684\u7f16\u53f7\r\nDELIMITER \/\/\r\nCREATE FUNCTION rand_num (from_num INT ,to_num INT) RETURNS INT(11)\r\nBEGIN\r\n    DECLARE i INT DEFAULT 0;\r\n    SET i = FLOOR(from_num +RAND()*(to_num- from_num+1)) ;\r\n    RETURN i;\r\nEND \/\/\r\nDELIMITER ;\r\n#\u5047\u5982\u8981\u5220\u9664\r\n#drop function rand_num;\r\n\r\n# \u6b65\u9aa44\uff1a\u521b\u5efa\u5b58\u50a8\u8fc7\u7a0b\r\n#\u521b\u5efa\u5f80stu\u8868\u4e2d\u63d2\u5165\u6570\u636e\u7684\u5b58\u50a8\u8fc7\u7a0b\r\nDELIMITER \/\/\r\nCREATE PROCEDURE insert_stu( START INT , max_num INT )\r\nBEGIN\r\n    DECLARE i INT DEFAULT 0;\r\n    SET autocommit = 0; #\u8bbe\u7f6e\u624b\u52a8\u63d0\u4ea4\u4e8b\u52a1\r\n    REPEAT #\u5faa\u73af\r\n        SET i = i + 1; #\u8d4b\u503c\r\n        INSERT INTO student (stuno, name ,age ,classId ) VALUES\r\n        ((START+i),rand_string(6),rand_num(1,50),rand_num(1,1000));\r\n        UNTIL i = max_num\r\n    END REPEAT;\r\n    COMMIT; #\u63d0\u4ea4\u4e8b\u52a1\r\nEND \/\/\r\nDELIMITER ;\r\n#\u5047\u5982\u8981\u5220\u9664\r\n#drop PROCEDURE insert_stu;\r\n\r\n# \u521b\u5efa\u5f80class\u8868\u4e2d\u63d2\u5165\u6570\u636e\u7684\u5b58\u50a8\u8fc7\u7a0b\r\n#\u6267\u884c\u5b58\u50a8\u8fc7\u7a0b\uff0c\u5f80class\u8868\u6dfb\u52a0\u968f\u673a\u6570\u636e\r\nDELIMITER \/\/\r\nCREATE PROCEDURE `insert_class`( max_num INT )\r\nBEGIN\r\n    DECLARE i INT DEFAULT 0;\r\n    SET autocommit = 0;\r\n    REPEAT\r\n        SET i = i + 1;\r\n        INSERT INTO class ( classname,address,monitor ) VALUES\r\n        (rand_string(8),rand_string(10),rand_num(1,100000));\r\n        UNTIL i = max_num\r\n    END REPEAT;\r\n    COMMIT;\r\nEND \/\/\r\nDELIMITER ;\r\n#\u5047\u5982\u8981\u5220\u9664\r\n#drop PROCEDURE insert_class;\r\n\r\n# \u6b65\u9aa45\uff1a\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\r\n#\u6267\u884c\u5b58\u50a8\u8fc7\u7a0b\uff0c\u5f80class\u8868\u6dfb\u52a01\u4e07\u6761\u6570\u636e\r\nCALL insert_class(10000);\r\n\r\n#\u6267\u884c\u5b58\u50a8\u8fc7\u7a0b\uff0c\u5f80stu\u8868\u6dfb\u52a050\u4e07\u6761\u6570\u636e\r\nCALL insert_stu(100000,500000);\r\n\r\nSELECT COUNT(*) FROM class;\r\n\r\nSELECT COUNT(*) FROM student;\r\n\r\n# \u6b65\u9aa46\uff1a\u5220\u9664\u67d0\u8868\u4e0a\u7684\u7d22\u5f15\r\n# \u521b\u5efa\u5b58\u50a8\u8fc7\u7a0b\r\nDELIMITER \/\/\r\nCREATE PROCEDURE `proc_drop_index`(dbname VARCHAR(200),tablename VARCHAR(200))\r\nBEGIN\r\n    DECLARE done INT DEFAULT 0;\r\n    DECLARE ct INT DEFAULT 0;\r\n    DECLARE _index VARCHAR(200) DEFAULT '';\r\n    DECLARE _cur CURSOR FOR SELECT index_name FROM information_schema.STATISTICS\r\n    WHERE table_schema=dbname AND table_name=tablename AND seq_in_index=1\r\n    AND index_name &lt;>'PRIMARY' ;\r\n    #\u6bcf\u4e2a\u6e38\u6807\u5fc5\u987b\u4f7f\u7528\u4e0d\u540c\u7684declare continue handler for not found set done=1\u6765\u63a7\u5236\u6e38\u6807\u7684\u7ed3\u675f\r\n    DECLARE CONTINUE HANDLER FOR NOT FOUND set done=2 ;\r\n    #\u82e5\u6ca1\u6709\u6570\u636e\u8fd4\u56de,\u7a0b\u5e8f\u7ee7\u7eed,\u5e76\u5c06\u53d8\u91cfdone\u8bbe\u4e3a2\r\n    OPEN _cur;\r\n    FETCH _cur INTO _index;\r\n    WHILE _index&lt;>'' DO\r\n        SET @str = CONCAT(\"drop index \" , _index , \" on \" , tablename );\r\n        PREPARE sql_str FROM @str ;\r\n        EXECUTE sql_str;\r\n        DEALLOCATE PREPARE sql_str;\r\n        SET _index='';\r\n        FETCH _cur INTO _index;\r\n    END WHILE;\r\n    CLOSE _cur;\r\nEND \/\/\r\nDELIMITER ;\r\n\r\n# \u6267\u884c\u5b58\u50a8\u8fc7\u7a0b\r\n\r\nCALL proc_drop_index(\"dbname\",\"tablename\");\r\n\r\n# 2. \u7d22\u5f15\u5931\u6548\u6848\u4f8b\r\n\r\n# 2.1 \u5168\u503c\u5339\u914d\u6211\u6700\u7231\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age=30;\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age=30 AND classId=4;\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age=30 AND classId=4 AND name = 'abcd';\r\n\r\nSELECT SQL_NO_CACHE * FROM student WHERE age=30 AND classId=4 AND name = 'abcd';\r\n#165 ms     #61 ms      #40 ms       #21 ms\r\n\r\nCREATE INDEX idx_age ON student(age);\r\n\r\nCREATE INDEX idx_age_classid ON student(age,classId);\r\n\r\nCREATE INDEX idx_age_classid_name ON student(age,classId,name);\r\n\r\n# 2.2 \u6700\u4f73\u5de6\u524d\u7f00\u6cd5\u5219\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE student.age=30 AND student.name = 'abcd';\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE student.classId=1 AND student.name = 'abcd';\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student\r\nWHERE classId=4 AND student.age=30 AND student.name = 'abcd';\r\n\r\nDROP INDEX idx_age ON student;\r\n\r\nDROP INDEX idx_age_classid ON student;\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student\r\nWHERE student.age=30 AND student.name = 'abcd';\r\n\r\n# 2.3 \u4e3b\u952e\u63d2\u5165\u987a\u5e8f\r\n\r\n# 2.4 \u8ba1\u7b97\u3001\u51fd\u6570\u3001\u7c7b\u578b\u8f6c\u6362(\u81ea\u52a8\u6216\u624b\u52a8)\u5bfc\u81f4\u7d22\u5f15\u5931\u6548\r\n\r\n#\u6b64\u8bed\u53e5\u6bd4\u4e0b\u4e00\u6761\u8981\u597d\uff01\uff08\u80fd\u591f\u4f7f\u7528\u4e0a\u7d22\u5f15\uff09\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE student.name LIKE 'abc%';\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE LEFT(student.name,3) = 'abc';\r\n\r\nCREATE INDEX idx_name ON student(name);\r\n\r\n# \u518d\u4e3e\u4f8b\uff1a\r\nCREATE INDEX idx_sno ON student(stuno);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE id, stuno, NAME FROM student WHERE stuno+1 = 900001;    #135 ms\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE id, stuno, NAME FROM student WHERE stuno = 900000;  #31 ms\r\n\r\n# \u518d\u4e3e\u4f8b\uff1a\r\n\r\nEXPLAIN SELECT id,stuno,name FROM student WHERE SUBSTRING(name, 1,3)='abc';\r\n\r\n# 2.5 \u7c7b\u578b\u8f6c\u6362\u5bfc\u81f4\u7d22\u5f15\u5931\u6548\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE name = 123;\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE name = '123';\r\n\r\n# 2.6 \u8303\u56f4\u6761\u4ef6\u53f3\u8fb9\u7684\u5217\u7d22\u5f15\u5931\u6548\r\n\r\nSHOW INDEX FROM student;\r\n\r\nCALL proc_drop_index('atguigudb2','student');\r\n\r\nCREATE INDEX idx_age_classId_name ON student(age,classId,name);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student\r\nWHERE student.age=30 AND student.classId>20 AND student.name = 'abc' ;\r\n\r\nCREATE INDEX idx_age_name_cid ON student(age,name,classId);\r\n\r\n# 2.7 \u4e0d\u7b49\u4e8e(!= \u6216\u8005&lt;>)\u7d22\u5f15\u5931\u6548\r\n\r\nCREATE INDEX idx_name ON student(name);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE student.name &lt;> 'abc';\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE student.name != 'abc';\r\n\r\n# 2.8 is null\u53ef\u4ee5\u4f7f\u7528\u7d22\u5f15\uff0cis not null\u65e0\u6cd5\u4f7f\u7528\u7d22\u5f15\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age IS NULL;\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age IS NOT NULL;\r\n\r\n# 2.9 like\u4ee5\u901a\u914d\u7b26%\u5f00\u5934\u7d22\u5f15\u5931\u6548\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE name LIKE 'ab%';\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE name LIKE '%ab%';\r\n\r\n# 2.10 OR \u524d\u540e\u5b58\u5728\u975e\u7d22\u5f15\u7684\u5217\uff0c\u7d22\u5f15\u5931\u6548\r\n\r\nSHOW INDEX FROM student;\r\n\r\nCALL proc_drop_index('atguigudb2','student');\r\n\r\nCREATE INDEX idx_age ON student(age);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age = 10 OR classid = 100;\r\n\r\nCREATE INDEX idx_cid ON student(classId);\r\n\r\n# 2.11 \u6570\u636e\u5e93\u548c\u8868\u7684\u5b57\u7b26\u96c6\u7edf\u4e00\u4f7f\u7528utf8mb4\r\n\r\n# 3. \u5173\u8054\u67e5\u8be2\u4f18\u5316\r\n\r\n# 3.1 \u6570\u636e\u51c6\u5907\r\n#\u5206\u7c7b\r\nCREATE TABLE IF NOT EXISTS `type` (\r\n`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,\r\n`card` INT(10) UNSIGNED NOT NULL,\r\nPRIMARY KEY (`id`)\r\n);\r\n\r\n#\u56fe\u4e66\r\nCREATE TABLE IF NOT EXISTS `book` (\r\n`bookid` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,\r\n`card` INT(10) UNSIGNED NOT NULL,\r\nPRIMARY KEY (`bookid`)\r\n);\r\n\r\n#\u5411\u5206\u7c7b\u8868\u4e2d\u6dfb\u52a020\u6761\u8bb0\u5f55\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\n\r\n#\u5411\u56fe\u4e66\u8868\u4e2d\u6dfb\u52a020\u6761\u8bb0\u5f55\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO book(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` LEFT JOIN book ON type.card = book.card;\r\n\r\n# 3.2 \u91c7\u7528\u5de6\u5916\u8fde\u63a5\r\n\r\n# \u60c5\u51b51\uff1a\u5de6\u5916\u8fde\u63a5\r\n\r\n#\u6dfb\u52a0\u7d22\u5f15\r\nCREATE INDEX Y ON book(card);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` LEFT JOIN book ON type.card = book.card;\r\n\r\nCREATE INDEX X ON type(card);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` LEFT JOIN book ON type.card = book.card;\r\n\r\nDROP INDEX Y ON book;\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` LEFT JOIN book ON type.card = book.card;\r\n\r\n# 3.3 \u91c7\u7528\u5185\u8fde\u63a5\r\n\r\n# \u60c5\u51b52\uff1a\u5185\u8fde\u63a5\r\n\r\nDROP INDEX X ON type;\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` INNER JOIN book ON type.card = book.card;\r\n\r\n#\u6dfb\u52a0\u7d22\u5f15\r\nCREATE INDEX Y ON book(card);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` INNER JOIN book ON type.card = book.card;\r\n\r\nCREATE INDEX X ON type(card);\r\n\r\n#\u7ed3\u8bba\uff1a\u5bf9\u4e8e\u5185\u8fde\u63a5\u6765\u8bf4\uff0c\u67e5\u8be2\u4f18\u5316\u5668\u53ef\u4ee5\u51b3\u5b9a\u8c01\u4f5c\u4e3a\u9a71\u52a8\u8868\uff0c\u8c01\u4f5c\u4e3a\u88ab\u9a71\u52a8\u8868\u51fa\u73b0\u7684\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` INNER JOIN book ON type.card = book.card;\r\n\r\n#\u5220\u9664\u7d22\u5f15\r\nDROP INDEX Y ON book;\r\n\r\n#\u7ed3\u8bba\uff1a\u5bf9\u4e8e\u5185\u8fde\u63a5\u6765\u8bb2\uff0c\u5982\u679c\u8868\u7684\u8fde\u63a5\u6761\u4ef6\u4e2d\u53ea\u80fd\u6709\u4e00\u4e2a\u5b57\u6bb5\u6709\u7d22\u5f15\uff0c\u5219\u6709\u7d22\u5f15\u7684\u5b57\u6bb5\u6240\u5728\u7684\u8868\u4f1a\u88ab\u4f5c\u4e3a\u88ab\u9a71\u52a8\u8868\u51fa\u73b0\u3002\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` INNER JOIN book ON type.card = book.card;\r\n\r\nCREATE INDEX Y ON book(card);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` INNER JOIN book ON type.card = book.card;\r\n\r\n#\u5411type\u8868\u4e2d\u6dfb\u52a0\u6570\u636e\uff0820\u6761\u6570\u636e\uff09\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\nINSERT INTO type(card) VALUES(FLOOR(1 + (RAND() * 20)));\r\n\r\n#\u7ed3\u8bba\uff1a\u5bf9\u4e8e\u5185\u8fde\u63a5\u6765\u8bf4\uff0c\u5728\u4e24\u4e2a\u8868\u7684\u8fde\u63a5\u6761\u4ef6\u90fd\u5b58\u5728\u7d22\u5f15\u7684\u60c5\u51b5\u4e0b\uff0c\u4f1a\u9009\u62e9\u5c0f\u8868\u4f5c\u4e3a\u9a71\u52a8\u8868\u3002\"\u5c0f\u8868\u9a71\u52a8\u5927\u8868\"\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM `type` INNER JOIN book ON type.card = book.card;\r\n\r\n# 3.4 JOIN\u8bed\u53e5\u539f\u7406\r\n\r\n#JOIN\u7684\u5e95\u5c42\u539f\u7406\r\n# \u2460 \u9a71\u52a8\u8868\u548c\u88ab\u9a71\u52a8\u8868\r\nCREATE TABLE a(f1 INT, f2 INT, INDEX(f1))ENGINE=INNODB;\r\n\r\nCREATE TABLE b(f1 INT, f2 INT)ENGINE=INNODB;\r\n\r\nINSERT INTO a VALUES(1,1),(2,2),(3,3),(4,4),(5,5),(6,6);\r\n\r\nINSERT INTO b VALUES(3,3),(4,4),(5,5),(6,6),(7,7),(8,8);\r\n\r\n#\u6d4b\u8bd51\r\nEXPLAIN SELECT * FROM a LEFT JOIN b ON(a.f1=b.f1) WHERE (a.f2=b.f2);\r\n\r\n#\u6d4b\u8bd52\r\nEXPLAIN SELECT * FROM a LEFT JOIN b ON(a.f1=b.f1) AND (a.f2=b.f2);\r\n\r\n#\u6d4b\u8bd53\r\nEXPLAIN SELECT * FROM a JOIN b ON(a.f1=b.f1) WHERE (a.f2=b.f2);\r\n\r\n# \u2461 Simple Nested-Loop Join(\u7b80\u5355\u5d4c\u5957\u5faa\u73af\u8fde\u63a5)\r\n\r\n# \u2462 Index Nested-Loop Join(\u7d22\u5f15\u5d4c\u5957\u5faa\u73af\u8fde\u63a5)\r\n\r\n# \u2463 Block Nested-Loop Join(\u5757\u5d4c\u5957\u5faa\u73af\u8fde\u63a5)\r\nSHOW VARIABLES LIKE '%optimizer_switch%';\r\n\r\nSHOW VARIABLES LIKE '%join_buffer%';\r\n\r\n# \u2464 \u5c0f\u7ed3\r\n# 1. \u6574\u4f53\u6548\u7387\u6bd4\u8f83\uff1aINLJ > BNLJ > SNLJ\r\n# 2. \u6c38\u8fdc\u7528\u5c0f\u7ed3\u679c\u96c6\u9a71\u52a8\u5927\u7ed3\u679c\u96c6\uff08\u5176\u672c\u8d28\u5c31\u662f\u51cf\u5c11\u5916\u5c42\u5faa\u73af\u7684\u6570\u636e\u6570\u91cf\uff09\uff08\u5c0f\u7684\u5ea6\u91cf\u5355\u4f4d\u6307\u7684\u662f \u8868\u884c\u6570*\u6bcf\u884c\u5927\u5c0f\uff09\r\nSELECT t1.b,t2 * FROM t1 STRAIGHT_JOIN t2 ON (t1.b=t2.b) WHERE t2.id &lt;= 100;    #\u63a8\u8350\r\nSELECT t1.b,t2 * FROM t2 STRAIGHT_JOIN t1 ON (t1.b=t2.b) WHERE t2.id &lt;= 100;    #\u4e0d\u63a8\u8350\r\n# 3. \u4e3a\u88ab\u9a71\u52a8\u8868\u5339\u914d\u7684\u6761\u4ef6\u589e\u52a0\u7d22\u5f15\uff08\u51cf\u5c11\u5185\u5c42\u8868\u7684\u5faa\u73af\u5339\u914d\u6b21\u6570\uff09\r\n# 4. \u589e\u5927join buffer size\u7684\u5927\u5c0f\uff08\u4e00\u6b21\u7f13\u5b58\u7684\u6570\u636e\u8d8a\u591a\uff0c\u90a3\u4e48\u5185\u5c42\u5305\u7684\u626b\u8868\u6b21\u6570\u8d8a\u5c11\uff09\r\n# 5. \u51cf\u5c11\u9a71\u52a8\u8868\u4e0d\u5fc5\u8981\u7684\u5b57\u6bb5\u67e5\u8be2\uff08\u5b57\u6bb5\u8d8a\u5c11\uff0cjoin buffer \u6240\u7f13\u5b58\u7684\u6570\u636e\u5c31\u8d8a\u591a\uff09\r\n\r\n# 4. \u5b50\u67e5\u8be2\u4f18\u5316\r\n\r\n#\u521b\u5efa\u73ed\u7ea7\u8868\u4e2d\u73ed\u957f\u7684\u7d22\u5f15\r\nCREATE INDEX idx_monitor ON class(monitor);\r\n\r\n#\u67e5\u8be2\u73ed\u957f\u7684\u4fe1\u606f\r\nEXPLAIN SELECT * FROM student stu1\r\nWHERE stu1.`stuno` IN (\r\nSELECT monitor\r\nFROM class c\r\nWHERE monitor IS NOT NULL\r\n);\r\n\r\nEXPLAIN SELECT stu1.* FROM student stu1 JOIN class c\r\nON stu1.`stuno` = c.`monitor`\r\nWHERE c.`monitor` IS NOT NULL;\r\n\r\n#\u67e5\u8be2\u4e0d\u4e3a\u73ed\u957f\u7684\u5b66\u751f\u4fe1\u606f\r\nEXPLAIN SELECT SQL_NO_CACHE a.*\r\nFROM student a\r\nWHERE  a.stuno  NOT  IN (\r\n\t\t\tSELECT monitor FROM class b\r\n\t\t\tWHERE monitor IS NOT NULL);\r\n\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE a.*\r\nFROM  student a LEFT OUTER JOIN class b\r\nON a.stuno =b.monitor\r\nWHERE b.monitor IS NULL;\r\n\r\n# 5. \u6392\u5e8f\u4f18\u5316\r\n\r\n# 5.1 \u6392\u5e8f\u4f18\u5316\r\n# \u4f18\u5316\u5efa\u8bae\uff1a\r\n# 1. SQL \u4e2d\uff0c\u53ef\u4ee5\u5728 WHERE \u5b50\u53e5\u548c ORDER BY \u5b50\u53e5\u4e2d\u4f7f\u7528\u7d22\u5f15\uff0c\r\n# \u76ee\u7684\u662f\u5728 WHERE \u5b50\u53e5\u4e2d \u907f\u514d\u5168\u8868\u626b\u63cf \uff0c\u5728 ORDER BY \u5b50\u53e5 \u907f\u514d\u4f7f\u7528 FileSort \u6392\u5e8f \u3002\r\n# \u5f53\u7136\uff0c\u67d0\u4e9b\u60c5\u51b5\u4e0b\u5168\u8868\u626b\u63cf\uff0c\u6216\u8005 FileSort \u6392\u5e8f\u4e0d\u4e00\u5b9a\u6bd4\u7d22\u5f15\u6162\u3002\u4f46\u603b\u7684\u6765\u8bf4\uff0c\u6211\u4eec\u8fd8\u662f\u8981\u907f\u514d\uff0c\u4ee5\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\u3002\r\n# 2. \u5c3d\u91cf\u4f7f\u7528 Index \u5b8c\u6210 ORDER BY \u6392\u5e8f\u3002\r\n# \u5982\u679c WHERE \u548c ORDER BY \u540e\u9762\u662f\u76f8\u540c\u7684\u5217\u5c31\u4f7f\u7528\u5355\u7d22\u5f15\u5217\uff1b\u5982\u679c\u4e0d\u540c\u5c31\u4f7f\u7528\u8054\u5408\u7d22\u5f15\u3002\r\n# 3. \u65e0\u6cd5\u4f7f\u7528 Index \u65f6\uff0c\u9700\u8981\u5bf9 FileSort \u65b9\u5f0f\u8fdb\u884c\u8c03\u4f18\u3002\r\n\r\n# 5.2 \u6d4b\u8bd5\r\n#\u5220\u9664student\u548cclass\u8868\u4e2d\u7684\u975e\u4e3b\u952e\u7d22\u5f15\r\nCALL proc_drop_index('atguigudb2','student');\r\nCALL proc_drop_index('atguigudb2','class');\r\n\r\nSHOW INDEX FROM student;\r\nSHOW INDEX FROM class;\r\n\r\n#\u8fc7\u7a0b\u4e00\uff1a\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student ORDER BY age,classid;\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student ORDER BY age,classid LIMIT 10;\r\n\r\n#\u8fc7\u7a0b\u4e8c\uff1aorder by\u65f6\u4e0dlimit\uff0c\u7d22\u5f15\u5931\u6548\r\n#\u521b\u5efa\u7d22\u5f15\r\nCREATE  INDEX idx_age_classid_name ON student (age,classid,NAME);\r\n\r\n#\u4e0d\u9650\u5236,\u7d22\u5f15\u5931\u6548\r\nEXPLAIN  SELECT SQL_NO_CACHE * FROM student ORDER BY age,classid;\r\n\r\n#EXPLAIN  SELECT SQL_NO_CACHE age,classid,name,id FROM student ORDER BY age,classid;\r\n\r\n#\u589e\u52a0limit\u8fc7\u6ee4\u6761\u4ef6\uff0c\u4f7f\u7528\u4e0a\u7d22\u5f15\u4e86\u3002\r\nEXPLAIN  SELECT SQL_NO_CACHE * FROM student ORDER BY age,classid LIMIT 10;\r\n\r\n#\u8fc7\u7a0b\u4e09\uff1aorder by\u65f6\u987a\u5e8f\u9519\u8bef\uff0c\u7d22\u5f15\u5931\u6548\r\n\r\n#\u521b\u5efa\u7d22\u5f15age,classid,stuno\r\nCREATE  INDEX idx_age_classid_stuno ON student (age,classid,stuno);\r\n\r\n#\u4ee5\u4e0b\u54ea\u4e9b\u7d22\u5f15\u5931\u6548?\r\nEXPLAIN  SELECT * FROM student ORDER BY classid LIMIT 10;\r\n\r\nEXPLAIN  SELECT * FROM student ORDER BY classid,NAME LIMIT 10;\r\n\r\nEXPLAIN  SELECT * FROM student ORDER BY age,classid,stuno LIMIT 10;\r\n\r\nEXPLAIN  SELECT * FROM student ORDER BY age,classid LIMIT 10;\r\n\r\nEXPLAIN  SELECT * FROM student ORDER BY age LIMIT 10;\r\n\r\n#\u8fc7\u7a0b\u56db\uff1aorder by\u65f6\u89c4\u5219\u4e0d\u4e00\u81f4, \u7d22\u5f15\u5931\u6548 \uff08\u987a\u5e8f\u9519\uff0c\u4e0d\u7d22\u5f15\uff1b\u65b9\u5411\u53cd\uff0c\u4e0d\u7d22\u5f15\uff09\r\n\r\nEXPLAIN  SELECT * FROM student ORDER BY age DESC, classid ASC LIMIT 10;\r\n\r\nEXPLAIN  SELECT * FROM student ORDER BY classid DESC, NAME DESC LIMIT 10;\r\n\r\nEXPLAIN  SELECT * FROM student ORDER BY age ASC,classid DESC LIMIT 10;\r\n\r\nEXPLAIN  SELECT * FROM student ORDER BY age DESC, classid DESC LIMIT 10;\r\n\r\n#\u8fc7\u7a0b\u4e94\uff1a\u65e0\u8fc7\u6ee4\uff0c\u4e0d\u7d22\u5f15\r\n\r\nEXPLAIN  SELECT * FROM student WHERE age=45 ORDER BY classid;\r\n\r\nEXPLAIN  SELECT * FROM student WHERE  age=45 ORDER BY classid,NAME;\r\n\r\nEXPLAIN  SELECT * FROM student WHERE  classid=45 ORDER BY age;\r\n\r\nEXPLAIN  SELECT * FROM student WHERE  classid=45 ORDER BY age LIMIT 10;\r\n\r\nCREATE INDEX idx_cid ON student(classid);\r\nEXPLAIN  SELECT * FROM student WHERE  classid=45 ORDER BY age;\r\n\r\n#\u5c0f\u7ed3\r\n# INDEX a_b_c(a,b,c)\r\n\r\n# order by \u80fd\u4f7f\u7528\u7d22\u5f15\u6700\u5de6\u524d\u7f00\r\n# - ORDER BY a\r\n# - ORDER BY a,b\r\n# - ORDER BY a,b,c\r\n# - ORDER BY a DESC,b DESC,c DESC\r\n\r\n# \u5982\u679cWHERE\u4f7f\u7528\u7d22\u5f15\u7684\u6700\u5de6\u524d\u7f00\u5b9a\u4e49\u4e3a\u5e38\u91cf\uff0c\u5219order by \u80fd\u4f7f\u7528\u7d22\u5f15\r\n# - WHERE a = const ORDER BY b,c\r\n# - WHERE a = const AND b = const ORDER BY c\r\n# - WHERE a = const ORDER BY b,c\r\n# - WHERE a = const AND b > const ORDER BY b,c\r\n\r\n# \u4e0d\u80fd\u4f7f\u7528\u7d22\u5f15\u8fdb\u884c\u6392\u5e8f\r\n# - ORDER BY a ASC,b DESC,c DESC \/* \u6392\u5e8f\u4e0d\u4e00\u81f4 *\/\r\n# - WHERE g = const ORDER BY b,c \/*\u4e22\u5931a\u7d22\u5f15*\/\r\n# - WHERE a = const ORDER BY c \/*\u4e22\u5931b\u7d22\u5f15*\/\r\n# - WHERE a = const ORDER BY a,d \/*d\u4e0d\u662f\u7d22\u5f15\u7684\u4e00\u90e8\u5206*\/\r\n# - WHERE a in (...) ORDER BY b,c \/*\u5bf9\u4e8e\u6392\u5e8f\u6765\u8bf4\uff0c\u591a\u4e2a\u76f8\u7b49\u6761\u4ef6\u4e5f\u662f\u8303\u56f4\u67e5\u8be2*\/\r\n\r\n# 5.3 \u6848\u4f8b\u5b9e\u6218\r\n\r\n#\u5b9e\u6218\uff1a\u6d4b\u8bd5filesort\u548cindex\u6392\u5e8f\r\nCALL proc_drop_index('atguigudb2','student');\r\n\r\n# \u573a\u666f:\u67e5\u8be2\u5e74\u9f84\u4e3a30\u5c81\u7684\uff0c\u4e14\u5b66\u751f\u7f16\u53f7\u5c0f\u4e8e101000\u7684\u5b66\u751f\uff0c\u6309\u7528\u6237\u540d\u79f0\u6392\u5e8f\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age = 30 AND stuno &lt;101000 ORDER BY NAME; #143 ms\r\n\r\n# \u65b9\u6848\u4e00: \u4e3a\u4e86\u53bb\u6389filesort\u6211\u4eec\u53ef\u4ee5\u628a\u7d22\u5f15\u5efa\u6210\r\nCREATE INDEX idx_age_name ON student(age,name);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age = 30 AND stuno &lt;101000 ORDER BY NAME; #76 ms\r\n\r\n# \u65b9\u6848\u4e8c\uff1a\r\nCREATE INDEX idx_age_stuno_name ON student(age,stuno,name);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age = 30 AND stuno &lt;101000 ORDER BY NAME;  #43 ms\r\n\r\n# \u7ed3\u8bba\uff1a\r\n# 1. \u4e24\u4e2a\u7d22\u5f15\u540c\u65f6\u5b58\u5728\uff0cmysql\u81ea\u52a8\u9009\u62e9\u6700\u4f18\u7684\u65b9\u6848\u3002\uff08\u5bf9\u4e8e\u8fd9\u4e2a\u4f8b\u5b50\uff0cmysql\u9009\u62e9idx_age_stuno_name\uff09\u3002\r\n# \u4f46\u662f\uff0c \u968f\u7740\u6570\u636e\u91cf\u7684\u53d8\u5316\uff0c\u9009\u62e9\u7684\u7d22\u5f15\u4e5f\u4f1a\u968f\u4e4b\u53d8\u5316\u7684 \u3002\r\n# 2. \u5f53\u3010\u8303\u56f4\u6761\u4ef6\u3011\u548c\u3010group by \u6216\u8005 order by\u3011\u7684\u5b57\u6bb5\u51fa\u73b0\u4e8c\u9009\u4e00\u65f6\uff0c\r\n# \u4f18\u5148\u89c2\u5bdf\u6761\u4ef6\u5b57\u6bb5\u7684\u8fc7\u6ee4\u6570\u91cf\uff0c\u5982\u679c\u8fc7\u6ee4\u7684\u6570\u636e\u8db3\u591f\u591a\uff0c\u800c\u9700\u8981\u6392\u5e8f\u7684\u6570\u636e\u5e76\u4e0d\u591a\u65f6\uff0c\r\n# \u4f18\u5148\u628a\u7d22\u5f15\u653e\u5728\u8303\u56f4\u5b57\u6bb5\u4e0a\u3002\u53cd\u4e4b\uff0c\u4ea6\u7136\u3002\r\n\r\nDROP INDEX idx_age_stuno_name ON student;\r\n\r\nCREATE INDEX idx_age_stuno ON student(age,stuno);\r\n\r\nEXPLAIN SELECT SQL_NO_CACHE * FROM student WHERE age = 30 AND stuno &lt;101000 ORDER BY NAME;\r\n\r\n# 6. GROUP BY\u4f18\u5316\r\n\r\n# group by \u4f7f\u7528\u7d22\u5f15\u7684\u539f\u5219\u51e0\u4e4e\u8ddforder by\u4e00\u81f4 \uff0cgroup by \u5373\u4f7f\u6ca1\u6709\u8fc7\u6ee4\u6761\u4ef6\u7528\u5230\u7d22\u5f15\uff0c\u4e5f\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u7d22\u5f15\u3002\r\n\r\n# group by \u5148\u6392\u5e8f\u518d\u5206\u7ec4\uff0c\u9075\u7167\u7d22\u5f15\u5efa\u7684\u6700\u4f73\u5de6\u524d\u7f00\u6cd5\u5219\r\n\r\n# \u5f53\u65e0\u6cd5\u4f7f\u7528\u7d22\u5f15\u5217\uff0c\u589e\u5927 max_length_for_sort_data \u548c sort_buffer_size \u53c2\u6570\u7684\u8bbe\u7f6e\r\n\r\n# where\u6548\u7387\u9ad8\u4e8ehaving\uff0c\u80fd\u5199\u5728where\u9650\u5b9a\u7684\u6761\u4ef6\u5c31\u4e0d\u8981\u5199\u5728having\u4e2d\u4e86\r\n\r\n# \u51cf\u5c11\u4f7f\u7528order by\uff0c\u548c\u4e1a\u52a1\u6c9f\u901a\u80fd\u4e0d\u6392\u5e8f\u5c31\u4e0d\u6392\u5e8f\uff0c\u6216\u5c06\u6392\u5e8f\u653e\u5230\u7a0b\u5e8f\u7aef\u53bb\u505a\u3002\r\n# Order by\u3001group by\u3001distinct\u8fd9\u4e9b\u8bed\u53e5\u8f83\u4e3a\u8017\u8d39CPU\uff0c\u6570\u636e\u5e93\u7684CPU\u8d44\u6e90\u662f\u6781\u5176\u5b9d\u8d35\u7684\u3002\r\n\r\n# \u5305\u542b\u4e86order by\u3001group by\u3001distinct\u8fd9\u4e9b\u67e5\u8be2\u7684\u8bed\u53e5\uff0c\r\n# where\u6761\u4ef6\u8fc7\u6ee4\u51fa\u6765\u7684\u7ed3\u679c\u96c6\u8bf7\u4fdd\u6301\u57281000\u884c\u4ee5\u5185\uff0c\u5426\u5219SQL\u4f1a\u5f88\u6162\u3002\r\n\r\n# 7. \u4f18\u5316\u5206\u9875\u67e5\u8be2\r\n\r\nEXPLAIN SELECT * FROM student LIMIT 2000000,10;\r\n\r\n# \u4f18\u5316\u601d\u8def\u4e00\r\nEXPLAIN SELECT * FROM student t,(SELECT id FROM student ORDER BY id LIMIT 2000000,10) a\r\nWHERE t.id = a.id;\r\n\r\n# \u4f18\u5316\u601d\u8def\u4e8c\r\nEXPLAIN SELECT * FROM student WHERE id > 2000000 LIMIT 10;\r\n\r\n# 8. \u4f18\u5148\u8003\u8651\u8986\u76d6\u7d22\u5f15\r\n\r\n#\u5220\u9664\u4e4b\u524d\u7684\u7d22\u5f15\r\n#\u4e3e\u4f8b1\uff1a\r\nDROP INDEX idx_age_stuno ON student;\r\n\r\nCREATE INDEX idx_age_name ON student (age,NAME);\r\n\r\nEXPLAIN SELECT * FROM student WHERE age &lt;> 20;\r\n\r\nEXPLAIN SELECT age,NAME FROM student WHERE age &lt;> 20;\r\n\r\n#\u4e3e\u4f8b2\uff1a\r\nEXPLAIN SELECT * FROM student WHERE NAME LIKE '%abc';\r\n\r\nCREATE INDEX idx_age_name ON student (age,name);\r\n\r\nEXPLAIN SELECT id,age FROM student WHERE NAME LIKE '%abc';\r\n\r\n# 10. \u7d22\u5f15\u6761\u4ef6\u4e0b\u63a8(ICP)\r\n\r\n#\u4e3e\u4f8b1\uff1a\r\nUSE atguigudb1;\r\n\r\nEXPLAIN SELECT * FROM s1 WHERE key1 > 'z' AND key1 LIKE '%a';\r\n\r\n#\u4e3e\u4f8b2\uff1a\r\n# \u5efa\u8868\r\nCREATE TABLE `people` (\r\n      `id` INT NOT NULL AUTO_INCREMENT,\r\n      `zipcode` VARCHAR(20) COLLATE utf8_bin DEFAULT NULL,\r\n      `firstname` VARCHAR(20) COLLATE utf8_bin DEFAULT NULL,\r\n      `lastname` VARCHAR(20) COLLATE utf8_bin DEFAULT NULL,\r\n      `address` VARCHAR(50) COLLATE utf8_bin DEFAULT NULL,\r\n      PRIMARY KEY (`id`),\r\n      KEY `zip_last_first` (`zipcode`,`lastname`,`firstname`)\r\n) ENGINE=INNODB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb3 COLLATE=utf8_bin;\r\n\r\n# \u63d2\u5165\u6570\u636e\r\nINSERT INTO `people` VALUES\r\n    ('1', '000001', '\u4e09', '\u5f20', '\u5317\u4eac\u5e02'),\r\n    ('2', '000002', '\u56db', '\u674e', '\u5357\u4eac\u5e02'),\r\n    ('3', '000003', '\u4e94', '\u738b', '\u4e0a\u6d77\u5e02'),\r\n    ('4', '000001', '\u516d', '\u8d75', '\u5929\u6d25\u5e02');\r\n\r\n# \u67e5\u8be2\u64cd\u4f5c\r\nEXPLAIN SELECT * FROM people\r\nWHERE zipcode='000001'\r\nAND lastname LIKE '%\u5f20%'\r\nAND address LIKE '%\u5317\u4eac\u5e02%';\r\n\r\nEXPLAIN SELECT * FROM people\r\nWHERE zipcode='000001'\r\nAND lastname LIKE '\u5f20%'\r\nAND firstname LIKE '\u4e09%';\r\n\r\n#ICP\u7684\u5f00\u542f\/\u5173\u95ed\r\n\r\n#\u5173\u95ed\r\nSET optimizer_switch = 'index_condition_pushdown=off';\r\n\r\n#\u5f00\u542f\r\nSET optimizer_switch = 'index_condition_pushdown=on';\r\n\r\n# \u5f00\u542f\u548c\u5173\u95edICP\u7684\u6027\u80fd\u5bf9\u6bd4\r\n\r\n#\u521b\u5efa\u5b58\u50a8\u8fc7\u7a0b\uff0c\u5411people\u8868\u4e2d\u6dfb\u52a01000000\u6761\u6570\u636e\uff0c\u6d4b\u8bd5ICP\u5f00\u542f\u548c\u5173\u95ed\u72b6\u6001\u4e0b\u7684\u6027\u80fd\r\nDELIMITER \/\/\r\nCREATE PROCEDURE  insert_people( max_num INT )\r\nBEGIN\r\n    DECLARE i INT DEFAULT 0;\r\n    SET autocommit = 0;\r\n    REPEAT\r\n        SET i = i + 1;\r\n        INSERT INTO people ( zipcode,firstname,lastname,address ) VALUES ('000001', '\u516d', '\u8d75', '\u5929\u6d25\u5e02');\r\n        UNTIL i = max_num\r\n    END REPEAT;\r\n    COMMIT;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\r\nCALL insert_people(1000000);\r\n\r\n#\u9996\u5148\u6253\u5f00profiling\u3002\r\nSET PROFILING = 1;\r\n\r\n#\u6267\u884cSQL\u8bed\u53e5\uff0c\u6b64\u65f6\u9ed8\u8ba4\u6253\u5f00\u7d22\u5f15\u4e0b\u63a8\r\nSELECT * FROM people WHERE zipcode='000001' AND lastname LIKE '%\u5f20%';\r\n\r\n#\u518d\u6b21\u6267\u884cSQL\u8bed\u53e5\uff0c\u4e0d\u4f7f\u7528\u7d22\u5f15\u4e0b\u63a8\r\nSELECT \/*+ no_icp (people) *\/ * FROM people WHERE zipcode='000001' AND lastname LIKE '%\u5f20%';\r\n\r\n#\u67e5\u770b\u5f53\u524d\u4f1a\u8bdd\u6240\u4ea7\u751f\u7684\u6240\u6709profiles\r\nSHOW PROFILES;\r\n\r\n# 12. \u5176\u5b83\u67e5\u8be2\u4f18\u5316\u7b56\u7565\r\n\r\n# 12.1 EXISTS \u548c IN \u7684\u533a\u5206\r\n# \u7d22\u5f15\u662f\u4e2a\u524d\u63d0\uff0c\u5176\u5b9e\u9009\u62e9\u4e0e\u5426\u8fd8\u4f1a\u8981\u770b\u8868\u7684\u5927\u5c0f\u3002\u4f60\u53ef\u4ee5\u5c06\u9009\u62e9\u7684\u6807\u51c6\u7406\u89e3\u4e3a\u5c0f\u8868\u9a71\u52a8\u5927\u8868\u3002\r\n\r\n# 12.2 COUNT(*)\u4e0eCOUNT(\u5177\u4f53\u5b57\u6bb5)\u6548\u7387\r\n# \u73af\u82821\uff1aCOUNT(*)\u548cCOUNT(1)\u90fd\u662f\u5bf9\u6240\u6709\u7ed3\u679c\u8fdb\u884cCOUNT\uff0c\r\n# COUNT(*)\u548cCOUNT(1)\u672c\u8d28\u4e0a\u5e76\u6ca1\u6709\u533a\u522b\uff08\u4e8c\u8005\u6267\u884c\u65f6\u95f4\u53ef\u80fd\u7565\u6709\u5dee\u522b\uff0c\u4e0d\u8fc7\u4f60\u8fd8\u662f\u53ef\u4ee5\u628a\u5b83\u4fe9\u7684\u6267\u884c\u6548\u7387\u770b\u6210\u662f\u76f8\u7b49\u7684\uff09\u3002\r\n# \u5982\u679c\u6709WHERE\u5b50\u53e5\uff0c\u5219\u662f\u5bf9\u6240\u6709\u7b26\u5408\u7b5b\u9009\u6761\u4ef6\u7684\u6570\u636e\u884c\u8fdb\u884c\u7edf\u8ba1\uff1b\r\n# \u5982\u679c\u6ca1\u6709WHERE\u5b50\u53e5\uff0c\u5219\u662f\u5bf9\u6570\u636e\u8868\u7684\u6570\u636e\u884c\u6570\u8fdb\u884c\u7edf\u8ba1\u3002\r\n\r\n# **\u73af\u82822\uff1a\u5982\u679c\u662fMyISAM\u5b58\u50a8\u5f15\u64ce\uff0c\u7edf\u8ba1\u6570\u636e\u8868\u7684\u884c\u6570\u53ea\u9700\u8981O(1)\u7684\u590d\u6742\u5ea6\uff0c\r\n# \u8fd9\u662f\u56e0\u4e3a\u6bcf\u5f20MyISAM\u7684\u6570\u636e\u8868\u90fd\u6709\u4e00\u4e2ameta\u4fe1\u606f\u5b58\u50a8\u4e86row_count\u503c\uff0c\u800c\u4e00\u81f4\u6027\u5219\u662f\u7531\u8868\u7ea7\u9501\u6765\u4fdd\u8bc1\u7684\u3002\r\n\r\n# \u5982\u679c\u662fInnoDB\u5b58\u50a8\u5f15\u64ce\uff0c\u56e0\u4e3aInnoDB\u652f\u6301\u4e8b\u52a1\uff0c\u91c7\u7528\u884c\u7ea7\u9501\u548cMVCC\u673a\u5236\uff0c\r\n# \u6240\u4ee5\u65e0\u6cd5\u50cfMyISAM\u4e00\u6837\uff0c\u7ef4\u62a4\u4e00\u4e2arow_count\u53d8\u91cf\uff0c\u56e0\u6b64\u9700\u8981\u91c7\u7528\u626b\u63cf\u5168\u8868\uff0c\u662fO(n)\u7684\u590d\u6742\u5ea6\uff0c\r\n# \u8fdb\u884c\u5faa\u73af+\u8ba1\u6570\u7684\u65b9\u5f0f\u6765\u5b8c\u6210\u7edf\u8ba1\u3002\r\n\r\n# **\u73af\u82823\uff1a\u5728InnoDB\u5f15\u64ce\u4e2d\uff0c\u5982\u679c\u91c7\u7528COUNT(\u5177\u4f53\u5b57\u6bb5)\u6765\u7edf\u8ba1\u6570\u636e\u884c\u6570\uff0c\u8981\u5c3d\u91cf\u91c7\u7528\u4e8c\u7ea7\u7d22\u5f15\u3002\r\n# \u56e0\u4e3a\u4e3b\u952e\u91c7\u7528\u7684\u7d22\u5f15\u662f\u805a\u7c07\u7d22\u5f15\uff0c\u805a\u7c07\u7d22\u5f15\u5305\u542b\u7684\u4fe1\u606f\u591a\uff0c\u660e\u663e\u4f1a\u5927\u4e8e\u4e8c\u7ea7\u7d22\u5f15\uff08\u975e\u805a\u7c07\u7d22\u5f15\uff09\u3002\r\n# \u5bf9\u4e8eCOUNT(*)\u548cCOUNT(1)\u6765\u8bf4\uff0c\u5b83\u4eec\u4e0d\u9700\u8981\u67e5\u627e\u5177\u4f53\u7684\u884c\uff0c\u53ea\u662f\u7edf\u8ba1\u884c\u6570\uff0c\u7cfb\u7edf\u4f1a\u81ea\u52a8\u91c7\u7528\u5360\u7528\u7a7a\u95f4\u66f4\u5c0f\u7684\u4e8c\u7ea7\u7d22\u5f15\u6765\u8fdb\u884c\u7edf\u8ba1\u3002\r\n\r\n# \u5982\u679c\u6709\u591a\u4e2a\u4e8c\u7ea7\u7d22\u5f15\uff0c\u4f1a\u4f7f\u7528key_len\u5c0f\u7684\u4e8c\u7ea7\u7d22\u5f15\u8fdb\u884c\u626b\u63cf\u3002\u5f53\u6ca1\u6709\u4e8c\u7ea7\u7d22\u5f15\u7684\u65f6\u5019\uff0c\u624d\u4f1a\u91c7\u7528\u4e3b\u952e\u7d22\u5f15\u6765\u8fdb\u884c\u7edf\u8ba1\u3002\r\n\r\n# 12.3 \u5173\u4e8eSELECT(*)\r\n# \u5728\u8868\u67e5\u8be2\u4e2d\uff0c\u5efa\u8bae\u660e\u786e\u5b57\u6bb5\uff0c\u4e0d\u8981\u4f7f\u7528 * \u4f5c\u4e3a\u67e5\u8be2\u7684\u5b57\u6bb5\u5217\u8868\uff0c\u63a8\u8350\u4f7f\u7528SELECT &lt;\u5b57\u6bb5\u5217\u8868> \u67e5\u8be2\u3002\u539f\u56e0\uff1a\r\n\r\n# \u2460 MySQL \u5728\u89e3\u6790\u7684\u8fc7\u7a0b\u4e2d\uff0c\u4f1a\u901a\u8fc7\u67e5\u8be2\u6570\u636e\u5b57\u5178\u5c06\"*\"\u6309\u5e8f\u8f6c\u6362\u6210\u6240\u6709\u5217\u540d\uff0c\u8fd9\u4f1a\u5927\u5927\u7684\u8017\u8d39\u8d44\u6e90\u548c\u65f6\u95f4\u3002\r\n\r\n# \u2461 \u65e0\u6cd5\u4f7f\u7528\u8986\u76d6\u7d22\u5f15\r\n\r\n# 12.4 LIMIT 1 \u5bf9\u4f18\u5316\u7684\u5f71\u54cd\r\n# \u9488\u5bf9\u7684\u662f\u4f1a\u626b\u63cf\u5168\u8868\u7684 SQL \u8bed\u53e5\uff0c\u5982\u679c\u4f60\u53ef\u4ee5\u786e\u5b9a\u7ed3\u679c\u96c6\u53ea\u6709\u4e00\u6761\uff0c\u90a3\u4e48\u52a0\u4e0aLIMIT 1\u7684\u65f6\u5019\uff0c\r\n# \u5f53\u627e\u5230\u4e00\u6761\u7ed3\u679c\u7684\u65f6\u5019\u5c31\u4e0d\u4f1a\u7ee7\u7eed\u626b\u63cf\u4e86\uff0c\u8fd9\u6837\u4f1a\u52a0\u5feb\u67e5\u8be2\u901f\u5ea6\u3002\r\n\r\n# \u5982\u679c\u6570\u636e\u8868\u5df2\u7ecf\u5bf9\u5b57\u6bb5\u5efa\u7acb\u4e86\u552f\u4e00\u7d22\u5f15\uff0c\u90a3\u4e48\u53ef\u4ee5\u901a\u8fc7\u7d22\u5f15\u8fdb\u884c\u67e5\u8be2\uff0c\u4e0d\u4f1a\u5168\u8868\u626b\u63cf\u7684\u8bdd\uff0c\u5c31\u4e0d\u9700\u8981\u52a0\u4e0aLIMIT 1\u4e86\u3002\r\n\r\n# 12.5 \u591a\u4f7f\u7528COMMIT\r\n# \u53ea\u8981\u6709\u53ef\u80fd\uff0c\u5728\u7a0b\u5e8f\u4e2d\u5c3d\u91cf\u591a\u4f7f\u7528 COMMIT\uff0c\u8fd9\u6837\u7a0b\u5e8f\u7684\u6027\u80fd\u5f97\u5230\u63d0\u9ad8\uff0c\u9700\u6c42\u4e5f\u4f1a\u56e0\u4e3a COMMIT \u6240\u91ca\u653e\u7684\u8d44\u6e90\u800c\u51cf\u5c11\u3002\r\n\r\n# COMMIT \u6240\u91ca\u653e\u7684\u8d44\u6e90\uff1a\r\n\r\n# \u56de\u6eda\u6bb5\u4e0a\u7528\u4e8e\u6062\u590d\u6570\u636e\u7684\u4fe1\u606f\r\n\r\n# \u88ab\u7a0b\u5e8f\u8bed\u53e5\u83b7\u5f97\u7684\u9501\r\n\r\n# redo \/ undo log buffer \u4e2d\u7684\u7a7a\u95f4\r\n\r\n# \u7ba1\u7406\u4e0a\u8ff0 3 \u79cd\u8d44\u6e90\u4e2d\u7684\u5185\u90e8\u82b1\u8d39\r\n\r\n# 13. \u6dd8\u5b9d\u6570\u636e\u5e93\uff0c\u4e3b\u952e\u5982\u4f55\u8bbe\u8ba1\u7684\uff1f\r\n\r\n# 13.1 \u81ea\u589eID\u7684\u95ee\u9898\r\n\r\n# \u81ea\u589eID\u505a\u4e3b\u952e\uff0c\u7b80\u5355\u6613\u61c2\uff0c\u51e0\u4e4e\u6240\u6709\u6570\u636e\u5e93\u90fd\u652f\u6301\u81ea\u589e\u7c7b\u578b\uff0c\u53ea\u662f\u5b9e\u73b0\u4e0a\u5404\u81ea\u6709\u6240\u4e0d\u540c\u800c\u5df2\u3002\r\n# \u81ea\u589eID\u9664\u4e86\u7b80\u5355\uff0c\u5176\u4ed6\u90fd\u662f\u7f3a\u70b9\uff0c\u603b\u4f53\u6765\u770b\u5b58\u5728\u4ee5\u4e0b\u51e0\u65b9\u9762\u7684\u95ee\u9898\uff1a\r\n\r\n# 1. \u53ef\u9760\u6027\u4e0d\u9ad8\r\n# \u5b58\u5728\u81ea\u589eID\u56de\u6eaf\u7684\u95ee\u9898\uff0c\u8fd9\u4e2a\u95ee\u9898\u76f4\u5230\u6700\u65b0\u7248\u672c\u7684MySQL 8.0\u624d\u4fee\u590d\u3002\r\n\r\n# 2. \u5b89\u5168\u6027\u4e0d\u9ad8\r\n# \u5bf9\u5916\u66b4\u9732\u7684\u63a5\u53e3\u53ef\u4ee5\u975e\u5e38\u5bb9\u6613\u731c\u6d4b\u5bf9\u5e94\u7684\u4fe1\u606f\u3002\u6bd4\u5982\uff1a\/User\/1\/\u8fd9\u6837\u7684\u63a5\u53e3\uff0c\r\n# \u53ef\u4ee5\u975e\u5e38\u5bb9\u6613\u731c\u6d4b\u7528\u6237ID\u7684\u503c\u4e3a\u591a\u5c11\uff0c\u603b\u7528\u6237\u6570\u91cf\u6709\u591a\u5c11\uff0c\u4e5f\u53ef\u4ee5\u975e\u5e38\u5bb9\u6613\u5730\u901a\u8fc7\u63a5\u53e3\u8fdb\u884c\u6570\u636e\u7684\u722c\u53d6\u3002\r\n\r\n# 3. \u6027\u80fd\u5dee\r\n# \u81ea\u589eID\u7684\u6027\u80fd\u8f83\u5dee\uff0c\u9700\u8981\u5728\u6570\u636e\u5e93\u670d\u52a1\u5668\u7aef\u751f\u6210\u3002\r\n\r\n# 4. \u4ea4\u4e92\u591a\r\n# \u4e1a\u52a1\u8fd8\u9700\u8981\u989d\u5916\u6267\u884c\u4e00\u6b21\u7c7b\u4f3c last_insert_id() \u7684\u51fd\u6570\u624d\u80fd\u77e5\u9053\u521a\u624d\u63d2\u5165\u7684\u81ea\u589e\u503c\uff0c\r\n# \u8fd9\u9700\u8981\u591a\u4e00\u6b21\u7684\u7f51\u7edc\u4ea4\u4e92\u3002\u5728\u6d77\u91cf\u5e76\u53d1\u7684\u7cfb\u7edf\u4e2d\uff0c\u591a1\u6761SQL\uff0c\u5c31\u591a\u4e00\u6b21\u6027\u80fd\u4e0a\u7684\u5f00\u9500\u3002\r\n\r\n# 5. \u5c40\u90e8\u552f\u4e00\u6027\r\n# \u6700\u91cd\u8981\u7684\u4e00\u70b9\uff0c\u81ea\u589eID\u662f\u5c40\u90e8\u552f\u4e00\uff0c\u53ea\u5728\u5f53\u524d\u6570\u636e\u5e93\u5b9e\u4f8b\u4e2d\u552f\u4e00\uff0c\u800c\u4e0d\u662f\u5168\u5c40\u552f\u4e00\uff0c\r\n# \u5728\u4efb\u610f\u670d\u52a1\u5668\u95f4\u90fd\u662f\u552f\u4e00\u7684\u3002\u5bf9\u4e8e\u76ee\u524d\u5206\u5e03\u5f0f\u7cfb\u7edf\u6765\u8bf4\uff0c\u8fd9\u7b80\u76f4\u5c31\u662f\u5669\u68a6\u3002\r\n\r\n# 13.2 \u4e1a\u52a1\u5b57\u6bb5\u505a\u4e3b\u952e\r\n\r\n# \u5efa\u8bae\u5c3d\u91cf\u4e0d\u8981\u7528\u8ddf\u4e1a\u52a1\u6709\u5173\u7684\u5b57\u6bb5\u505a\u4e3b\u952e\u3002\u6bd5\u7adf\uff0c\u4f5c\u4e3a\u9879\u76ee\u8bbe\u8ba1\u7684\u6280\u672f\u4eba\u5458\uff0c\r\n# \u6211\u4eec\u8c01\u4e5f\u65e0\u6cd5\u9884\u6d4b\u5728\u9879\u76ee\u7684\u6574\u4e2a\u751f\u547d\u5468\u671f\u4e2d\uff0c\u54ea\u4e2a\u4e1a\u52a1\u5b57\u6bb5\u4f1a\u56e0\u4e3a\u9879\u76ee\u7684\u4e1a\u52a1\u9700\u6c42\u800c\u6709\u91cd\u590d\uff0c\r\n# \u6216\u8005\u91cd\u7528\u4e4b\u7c7b\u7684\u60c5\u51b5\u51fa\u73b0\u3002\r\n\r\n# \u7ecf\u9a8c\uff1a\r\n# \u521a\u5f00\u59cb\u4f7f\u7528 MySQL \u65f6\uff0c\u5f88\u591a\u4eba\u90fd\u5f88\u5bb9\u6613\u72af\u7684\u9519\u8bef\u662f\u559c\u6b22\u7528\u4e1a\u52a1\u5b57\u6bb5\u505a\u4e3b\u952e\uff0c\u60f3\u5f53\u7136\u5730\u8ba4\u4e3a\u4e86\u89e3\u4e1a\u52a1\u9700\u6c42\uff0c\r\n# \u4f46\u5b9e\u9645\u60c5\u51b5\u5f80\u5f80\u51fa\u4e4e\u610f\u6599\uff0c\u800c\u66f4\u6539\u4e3b\u952e\u8bbe\u7f6e\u7684\u6210\u672c\u975e\u5e38\u9ad8\u3002\r\n\r\n# 13.3 \u6dd8\u5b9d\u7684\u4e3b\u952e\u8bbe\u8ba1\r\n\r\n# \u5927\u80c6\u731c\u6d4b\uff0c\u6dd8\u5b9d\u7684\u8ba2\u5355ID\u8bbe\u8ba1\u5e94\u8be5\u662f\uff1a\r\n# \u8ba2\u5355ID = \u65f6\u95f4 + \u53bb\u91cd\u5b57\u6bb5 + \u7528\u6237ID\u540e6\u4f4d\u5c3e\u53f7\r\n# \u8fd9\u6837\u7684\u8bbe\u8ba1\u80fd\u505a\u5230\u5168\u5c40\u552f\u4e00\uff0c\u4e14\u5bf9\u5206\u5e03\u5f0f\u7cfb\u7edf\u67e5\u8be2\u53ca\u5176\u53cb\u597d\u3002\r\n\r\n# 13.4 \u63a8\u8350\u7684\u4e3b\u952e\u8bbe\u8ba1\r\n\r\n# \u975e\u6838\u5fc3\u4e1a\u52a1 \uff1a\u5bf9\u5e94\u8868\u7684\u4e3b\u952e\u81ea\u589eID\uff0c\u5982\u544a\u8b66\u3001\u65e5\u5fd7\u3001\u76d1\u63a7\u7b49\u4fe1\u606f\u3002\r\n# \u6838\u5fc3\u4e1a\u52a1 \uff1a\u4e3b\u952e\u8bbe\u8ba1\u81f3\u5c11\u5e94\u8be5\u662f\u5168\u5c40\u552f\u4e00\u4e14\u662f\u5355\u8c03\u9012\u589e\u3002\r\n# \u5168\u5c40\u552f\u4e00\u4fdd\u8bc1\u5728\u5404\u7cfb\u7edf\u4e4b\u95f4\u90fd\u662f\u552f\u4e00\u7684\uff0c\u5355\u8c03\u9012\u589e\u662f\u5e0c\u671b\u63d2\u5165\u65f6\u4e0d\u5f71\u54cd\u6570\u636e\u5e93\u6027\u80fd\u3002\r\n\r\n# \u8fd9\u91cc\u63a8\u8350\u6700\u7b80\u5355\u7684\u4e00\u79cd\u4e3b\u952e\u8bbe\u8ba1\uff1aUUID\u3002\r\n\r\n# UUID\u7684\u7279\u70b9\uff1a\r\n# \u5168\u5c40\u552f\u4e00\uff0c\u5360\u752836\u5b57\u8282\uff0c\u6570\u636e\u65e0\u5e8f\uff0c\u63d2\u5165\u6027\u80fd\u5dee\u3002\r\n\r\n# MySQL\u6570\u636e\u5e93\u7684UUID\u7ec4\u6210\u5982\u4e0b\u6240\u793a\uff1a\r\n# UUID = \u65f6\u95f4+UUID\u7248\u672c\uff0816\u5b57\u8282\uff09- \u65f6\u949f\u5e8f\u5217\uff084\u5b57\u8282\uff09- MAC\u5730\u5740\uff0812\u5b57\u8282\uff09\r\n\r\nSELECT UUID() FROM dual;\r\n\r\n# \u6539\u9020UUID\r\n# \u82e5\u5c06\u65f6\u95f4\u9ad8\u4f4e\u4f4d\u4e92\u6362\uff0c\u5219\u65f6\u95f4\u5c31\u662f\u5355\u8c03\u9012\u589e\u7684\u4e86\uff0c\u4e5f\u5c31\u53d8\u5f97\u5355\u8c03\u9012\u589e\u4e86\u3002\r\n# MySQL 8.0\u53ef\u4ee5\u66f4\u6362\u65f6\u95f4\u4f4e\u4f4d\u548c\u65f6\u95f4\u9ad8\u4f4d\u7684\u5b58\u50a8\u65b9\u5f0f\uff0c\u8fd9\u6837UUID\u5c31\u662f\u6709\u5e8f\u7684UUID\u4e86\u3002\r\n\r\n# MySQL 8.0\u8fd8\u89e3\u51b3\u4e86UUID\u5b58\u5728\u7684\u7a7a\u95f4\u5360\u7528\u7684\u95ee\u9898\uff0c\u9664\u53bb\u4e86UUID\u5b57\u7b26\u4e32\u4e2d\u65e0\u610f\u4e49\u7684\"-\"\u5b57\u7b26\u4e32\uff0c\r\n# \u5e76\u4e14\u5c06\u5b57\u7b26\u4e32\u7528\u4e8c\u8fdb\u5236\u7c7b\u578b\u4fdd\u5b58\uff0c\u8fd9\u6837\u5b58\u50a8\u7a7a\u95f4\u964d\u4f4e\u4e3a\u4e8616\u5b57\u8282\u3002\r\n\r\n# \u53ef\u4ee5\u901a\u8fc7MySQL8.0\u63d0\u4f9b\u7684uuid_to_bin\u51fd\u6570\u5b9e\u73b0\u4e0a\u8ff0\u529f\u80fd\uff0c\u540c\u6837\u7684\uff0c\r\n# MySQL\u4e5f\u63d0\u4f9b\u4e86bin_to_uuid\u51fd\u6570\u8fdb\u884c\u8f6c\u5316\uff1a\r\n\r\nSET @uuid = UUID();\r\n\r\nSELECT @uuid,UUID_TO_BIN(@uuid),UUID_TO_BIN(@uuid,TRUE);\r\n\r\n# \u901a\u8fc7\u51fd\u6570uuid_to_bin(@uuid,true)\u5c06UUID\u8f6c\u5316\u4e3a\u6709\u5e8fUUID\u4e86\u3002\u5168\u5c40\u552f\u4e00 + \u5355\u8c03\u9012\u589e\uff0c\r\n# \u8fd9\u4e0d\u5c31\u662f\u6211\u4eec\u60f3\u8981\u7684\u4e3b\u952e\uff01\r\n\r\n# 4\u3001\u6709\u5e8fUUID\u6027\u80fd\u6d4b\u8bd5\r\n# \u5728\u5f53\u4eca\u7684\u4e92\u8054\u7f51\u73af\u5883\u4e2d\uff0c\u975e\u5e38\u4e0d\u63a8\u8350\u81ea\u589eID\u4f5c\u4e3a\u4e3b\u952e\u7684\u6570\u636e\u5e93\u8bbe\u8ba1\u3002\r\n# \u66f4\u63a8\u8350\u7c7b\u4f3c\u6709\u5e8fUUID\u7684\u5168\u5c40\u552f\u4e00\u7684\u5b9e\u73b0\u3002\r\n\r\n# \u53e6\u5916\u5728\u771f\u5b9e\u7684\u4e1a\u52a1\u7cfb\u7edf\u4e2d\uff0c\u4e3b\u952e\u8fd8\u53ef\u4ee5\u52a0\u5165\u4e1a\u52a1\u548c\u7cfb\u7edf\u5c5e\u6027\uff0c\u5982\u7528\u6237\u7684\u5c3e\u53f7\uff0c\u673a\u623f\u7684\u4fe1\u606f\u7b49\u3002\r\n# \u8fd9\u6837\u7684\u4e3b\u952e\u8bbe\u8ba1\u5c31\u66f4\u4e3a\u8003\u9a8c\u67b6\u6784\u5e08\u7684\u6c34\u5e73\u4e86\u3002\r\n\r\n# \u5982\u679c\u4e0d\u662fMySQL8.0 \u80bf\u4e48\u529e\uff1f\r\n\r\n# \u624b\u52a8\u8d4b\u503c\u5b57\u6bb5\u505a\u4e3b\u952e\uff01\r\n\r\n# \u6bd4\u5982\uff0c\u8bbe\u8ba1\u5404\u4e2a\u5206\u5e97\u7684\u4f1a\u5458\u8868\u7684\u4e3b\u952e\uff0c\u56e0\u4e3a\u5982\u679c\u6bcf\u53f0\u673a\u5668\u5404\u81ea\u4ea7\u751f\u7684\u6570\u636e\u9700\u8981\u5408\u5e76\uff0c\r\n# \u5c31\u53ef\u80fd\u4f1a\u51fa\u73b0\u4e3b\u952e\u91cd\u590d\u7684\u95ee\u9898\u3002\r\n\r\n# \u53ef\u4ee5\u5728\u603b\u90e8 MySQL \u6570\u636e\u5e93\u4e2d\uff0c\u6709\u4e00\u4e2a\u7ba1\u7406\u4fe1\u606f\u8868\uff0c\u5728\u8fd9\u4e2a\u8868\u4e2d\u6dfb\u52a0\u4e00\u4e2a\u5b57\u6bb5\uff0c\r\n# \u4e13\u95e8\u7528\u6765\u8bb0\u5f55\u5f53\u524d\u4f1a\u5458\u7f16\u53f7\u7684\u6700\u5927\u503c\u3002\r\n\r\n# \u95e8\u5e97\u5728\u6dfb\u52a0\u4f1a\u5458\u7684\u65f6\u5019\uff0c\u5148\u5230\u603b\u90e8 MySQL \u6570\u636e\u5e93\u4e2d\u83b7\u53d6\u8fd9\u4e2a\u6700\u5927\u503c\uff0c\u5728\u8fd9\u4e2a\u57fa\u7840\u4e0a\u52a0 1\uff0c\r\n# \u7136\u540e\u7528\u8fd9\u4e2a\u503c\u4f5c\u4e3a\u65b0\u4f1a\u5458\u7684\u201cid\u201d\uff0c\u540c\u65f6\uff0c\u66f4\u65b0\u603b\u90e8 MySQL \u6570\u636e\u5e93\u7ba1\u7406\u4fe1\u606f\u8868\u4e2d\u7684\u5f53 \u524d\u4f1a\u5458\u7f16\u53f7\u7684\u6700\u5927\u503c\u3002\r\n\r\n# \u8fd9\u6837\u4e00\u6765\uff0c\u5404\u4e2a\u95e8\u5e97\u6dfb\u52a0\u4f1a\u5458\u7684\u65f6\u5019\uff0c\u90fd\u5bf9\u540c\u4e00\u4e2a\u603b\u90e8 MySQL \u6570\u636e\u5e93\u4e2d\u7684\u6570\u636e\u8868\u5b57\u6bb5\u8fdb \u884c\u64cd\u4f5c\uff0c\r\n# \u5c31\u89e3\u51b3\u4e86\u5404\u95e8\u5e97\u6dfb\u52a0\u4f1a\u5458\u65f6\u4f1a\u5458\u7f16\u53f7\u51b2\u7a81\u7684\u95ee\u9898\u3002\r\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[47],"class_list":["post-1634","post","type-post","status-publish","format-standard","hentry","category-mysql-code","tag-mysql"],"_links":{"self":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1634"}],"collection":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1634"}],"version-history":[{"count":1,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1634\/revisions"}],"predecessor-version":[{"id":1635,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1634\/revisions\/1635"}],"wp:attachment":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1634"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1634"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1634"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}