{"id":1574,"date":"2022-11-17T23:03:09","date_gmt":"2022-11-17T15:03:09","guid":{"rendered":"https:\/\/qaqaq.top\/?p=1574"},"modified":"2022-12-19T20:20:34","modified_gmt":"2022-12-19T12:20:34","slug":"%e7%ac%ac16%e7%ab%a0%e8%af%be%e5%90%8e%e7%bb%83%e4%b9%a0","status":"publish","type":"post","link":"https:\/\/qaqaq.top\/?p=1574","title":{"rendered":"\u7b2c16\u7ae0\u53d8\u91cf\u3001\u6d41\u7a0b\u63a7\u5236\u4e0e\u6e38\u6807\u8bfe\u540e\u7ec3\u4e60"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code># \u7b2c16\u7ae0_\u53d8\u91cf\u3001\u6d41\u7a0b\u63a7\u5236\u4e0e\u6e38\u6807\u8bfe\u540e\u7ec3\u4e60\n\n\/*\n \u53d8\u91cf\uff1a\n        \u7cfb\u7edf\u53d8\u91cf\uff08\u5168\u5c40\u7cfb\u7edf\u53d8\u91cf\u3001\u4f1a\u8bdd\u7cfb\u7edf\u53d8\u91cf\uff09\n\n        \u7528\u6237\u81ea\u5b9a\u4e49\u53d8\u91cf\uff08\u4f1a\u8bdd\u7528\u6237\u53d8\u91cf\u3001\u5c40\u90e8\u53d8\u91cf\uff09\n *\/\n\n# \u7ec3\u4e601\uff1a\u6d4b\u8bd5\u53d8\u91cf\u7684\u4f7f\u7528\n\n#\u5b58\u50a8\u51fd\u6570\u7684\u7ec3\u4e60\n\n#0.\u51c6\u5907\u5de5\u4f5c\nCREATE DATABASE test16_var_cursor;\n\nuse test16_var_cursor;\n\nCREATE TABLE employees\n    AS\n    SELECT * FROM atguigudb.`employees`;\n\nCREATE TABLE departments\n    AS\n    SELECT * FROM atguigudb.`departments`;\n\nSET GLOBAL log_bin_trust_function_creators = 1;\n\n#\u65e0\u53c2\u6709\u8fd4\u56de\n#1. \u521b\u5efa\u51fd\u6570get_count(),\u8fd4\u56de\u516c\u53f8\u7684\u5458\u5de5\u4e2a\u6570\nDELIMITER $\n\nCREATE FUNCTION get_count()\nRETURNS INT\nBEGIN\n    #\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\n    DECLARE emp_count INT;\n\n    SELECT COUNT(*) INTO emp_count FROM employees;\n\n    RETURN emp_count;\nEND $\n\nDELIMITER ;\n\n#\u8c03\u7528\nSELECT get_count();\n\n#\u6709\u53c2\u6709\u8fd4\u56de\n#2. \u521b\u5efa\u51fd\u6570ename_salary(),\u6839\u636e\u5458\u5de5\u59d3\u540d\uff0c\u8fd4\u56de\u5b83\u7684\u5de5\u8d44\nDELIMITER $\n\nCREATE FUNCTION ename_salary(emp_name VARCHAR(15))\nRETURNS DOUBLE\n\nBEGIN\n    #\u58f0\u660e\u53d8\u91cf\n    SET @sal = 0;   #\u5b9a\u4e49\u4e86\u4e00\u4e2a\u4f1a\u8bdd\u7528\u6237\u53d8\u91cf\n\n    #\u8d4b\u503c\n   SELECT salary INTO @sal FROM employees WHERE last_name = emp_name;\n\n   RETURN @sal;\n\nEND $\n\nDELIMITER ;\n\n#\u8c03\u7528\nSELECT ename_salary('Abel');\n\nSELECT @sal;\n\n#3. \u521b\u5efa\u51fd\u6570dept_sal() ,\u6839\u636e\u90e8\u95e8\u540d\uff0c\u8fd4\u56de\u8be5\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\nDELIMITER \/\/\n\nCREATE FUNCTION dept_sal(dept_name VARCHAR(15))\nRETURNS DOUBLE\n\nBEGIN\n    DECLARE avg_sal DOUBLE;\n\n    SELECT AVG(salary) INTO avg_sal\n    FROM employees e JOIN departments d\n    ON e.department_id = d.department_id\n    WHERE d.department_name = dept_name;\n\n    RETURN avg_sal;\n\nEND \/\/\n\nDELIMITER ;\n\nSELECT dept_sal('Marketing');\n\n#4. \u521b\u5efa\u51fd\u6570add_float()\uff0c\u5b9e\u73b0\u4f20\u5165\u4e24\u4e2afloat\uff0c\u8fd4\u56de\u4e8c\u8005\u4e4b\u548c\nDELIMITER \/\/\n\nCREATE FUNCTION add_float(value1 FLOAT,value2 FLOAT)\nRETURNS FLOAT\nBEGIN\n   DECLARE sum_val FLOAT;\n   SET sum_val = value1 + value2;\n   RETURN sum_val;\n\nEND \/\/\n\nDELIMITER ;\n\nSET @v1 := 12.2;\nSET @v2 = 2.3;\nSELECT add_float(@v1,@v2);\n\n# 2. \u6d41\u7a0b\u63a7\u5236\n\n\/*\n \u5206\u652f\uff1aif \\ case ... when \\ case when ...\n \u5faa\u73af\uff1aloop \\ while \\ repeat\n \u5176\u5b83\uff1aleave \\ iterate\n\n *\/\n\n#1. \u521b\u5efa\u51fd\u6570test_if_case()\uff0c\u5b9e\u73b0\u4f20\u5165\u6210\u7ee9\uff0c\u5982\u679c\u6210\u7ee9&gt;90,\u8fd4\u56deA\uff0c\u5982\u679c\u6210\u7ee9&gt;80,\u8fd4\u56deB\uff0c\u5982\u679c\u6210\u7ee9&gt;60,\u8fd4\u56deC\uff0c\u5426\u5219\u8fd4\u56deD\n#\u8981\u6c42\uff1a\u5206\u522b\u4f7f\u7528if\u7ed3\u6784\u548ccase\u7ed3\u6784\u5b9e\u73b0\n\n#\u65b9\u5f0f1\uff1a\nDELIMITER $\n\nCREATE FUNCTION test_if_case1(score DOUBLE)\nRETURNS CHAR\nBEGIN\n    #\u58f0\u660e\u53d8\u91cf\n    DECLARE score_level CHAR;\n\n    IF score &gt; 90\n        THEN SET score_level = 'A';\n    ELSEIF score &gt; 80\n        THEN SET score_level = 'B';\n    ELSEIF score &gt; 60\n        THEN SET score_level = 'C';\n    ELSE\n        SET score_level = 'D';\n        END IF;\n\n    #\u8fd4\u56de\n    RETURN score_level;\n\nEND $\n\nDELIMITER ;\n\nSELECT test_if_case1(56);\n\n#\u65b9\u5f0f2\uff1acase when ...\nDELIMITER $\n\nCREATE FUNCTION test_if_case2(score DOUBLE)\nRETURNS CHAR\nBEGIN\n\n    #\u58f0\u660e\u53d8\u91cf\n    DECLARE score_level CHAR;\n\n    CASE\n        WHEN score &gt; 90 THEN SET score_level = 'A';\n        WHEN score &gt; 80 THEN SET score_level = 'B';\n        WHEN score &gt; 60 THEN SET score_level = 'C';\n        ELSE SET score_level = 'D';\n        END CASE;\n\n    #\u8fd4\u56de\n    RETURN score_level;\n\nEND $\n\nDELIMITER ;\n\n#\u8c03\u7528\nSELECT test_if_case2(76);\n\n#2. \u521b\u5efa\u5b58\u50a8\u8fc7\u7a0btest_if_pro()\uff0c\u4f20\u5165\u5de5\u8d44\u503c\uff0c\u5982\u679c\u5de5\u8d44\u503c&lt;3000,\u5219\u5220\u9664\u5de5\u8d44\u4e3a\u6b64\u503c\u7684\u5458\u5de5\uff0c\n# \u5982\u679c3000 &lt;= \u5de5\u8d44\u503c &lt;= 5000,\u5219\u4fee\u6539\u6b64\u5de5\u8d44\u503c\u7684\u5458\u5de5\u85aa\u8d44\u6da81000\uff0c\u5426\u5219\u6da8\u5de5\u8d44500\n\nDELIMITER $\n\nCREATE PROCEDURE test_if_pro(IN sal DOUBLE)\nBEGIN\n    IF sal &lt; 3000\n        THEN DELETE FROM employees WHERE salary = sal;\n    ELSEIF sal &lt;= 5000\n        THEN UPDATE employees SET salary = salary + 1000 WHERE salary = sal;\n    ELSE\n        UPDATE employees SET salary = salary + 500 WHERE salary = sal;\n        END IF;\nEND $\n\nDELIMITER ;\n\nCALL test_if_pro(24000);\n\nSELECT * FROM employees;\n\n#3. \u521b\u5efa\u5b58\u50a8\u8fc7\u7a0binsert_data(),\u4f20\u5165\u53c2\u6570\u4e3a IN \u7684 INT \u7c7b\u578b\u53d8\u91cf insert_count,\u5b9e\u73b0\u5411admin\u8868\u4e2d\u6279\u91cf\u63d2\u5165insert_count\u6761\u8bb0\u5f55\n\nCREATE TABLE admin(\n    id INT PRIMARY KEY AUTO_INCREMENT,\n    user_name VARCHAR(25) NOT NULL,\n    user_pwd VARCHAR(35) NOT NULL\n);\n\nSELECT * FROM admin;\n\nDELIMITER $\n\nCREATE PROCEDURE insert_data(IN insert_count INT)\n\nBEGIN\n   #\u58f0\u660e\u53d8\u91cf\n    DECLARE init_count INT DEFAULT 1;   #\u2460 \u521d\u59cb\u5316\u6761\u4ef6\n\n   WHILE init_count &lt;= insert_count DO  #\u2461 \u5faa\u73af\u6761\u4ef6\n        #\u2462 \u5faa\u73af\u4f53\n       INSERT INTO admin(user_name, user_pwd) VALUES(CONCAT('richie-',init_count),ROUND(RAND() * 1000000));\n        #\u2463 \u8fed\u4ee3\u6761\u4ef6\n       SET init_count = init_count + 1;\n\n    END WHILE;\n\nEND $\n\nDELIMITER ;\n\n#\u8c03\u7528\nCALL insert_data(100);\n\n# 3. \u6e38\u6807\u7684\u4f7f\u7528\n\n# \u521b\u5efa\u5b58\u50a8\u8fc7\u7a0bupdate_salary()\uff0c\u53c2\u65701\u4e3a IN \u7684INT\u578b\u53d8\u91cfdept_id\uff0c\u8868\u793a\u90e8\u95e8id\uff1b\n# \u53c2\u65702\u4e3a IN\u7684INT\u578b\u53d8\u91cfchange_sal_count\uff0c\u8868\u793a\u8981\u8c03\u6574\u85aa\u8d44\u7684\u5458\u5de5\u4e2a\u6570\u3002\u67e5\u8be2\u6307\u5b9aid\u90e8\u95e8\u7684\u5458\u5de5\u4fe1\u606f\uff0c\n# \u6309\u7167salary\u5347\u5e8f\u6392\u5217\uff0c\u6839\u636ehire_date\u7684\u60c5\u51b5\uff0c\u8c03\u6574\u524dchange_sal_count\u4e2a\u5458\u5de5\u7684\u85aa\u8d44\uff0c\u8be6\u60c5\u5982\u4e0b\u3002\n# hire_date                                   salary\n# hire_date &lt; 1995                            salary = salary*1.2\n# hire_date &gt;=1995 and hire_date &lt;= 1998      salary = salary*1.15\n# hire_date &gt; 1998 and hire_date &lt;= 2001      salary = salary *1.10\n# hire_date &gt; 2001                            salary = salary * 1.05\n\nDELIMITER $\n\nCREATE PROCEDURE update_salary(IN dept_id INT,IN change_sal_count INT)\nBEGIN\n    #\u58f0\u660e\u53d8\u91cf\n    DECLARE emp_id INT; #\u8bb0\u5f55\u5458\u5de5id\n    DECLARE emp_hire_date DATE; #\u8bb0\u5f55\u5458\u5de5\u5165\u804c\u65f6\u95f4\n\n    DECLARE init_count INT DEFAULT 1; #\u7528\u4e8e\u8868\u793a\u5faa\u73af\u7ed3\u6784\u7684\u521d\u59cb\u5316\u6761\u4ef6\n    DECLARE add_sal_rate DOUBLE; #\u8bb0\u5f55\u6da8\u85aa\u7684\u6bd4\u4f8b\n\n    #\u58f0\u660e\u6e38\u6807\n    DECLARE emp_cursor CURSOR FOR SELECT employee_id,hire_date FROM employees\n        WHERE department_id = dept_id ORDER BY salary ASC;\n    #\u6253\u5f00\u6e38\u6807\n    OPEN emp_cursor;\n\n    WHILE init_count &lt;= change_sal_count DO\n        #\u4f7f\u7528\u6e38\u6807\n        FETCH emp_cursor INTO emp_id,emp_hire_date;\n\n        #\u83b7\u53d6\u6da8\u85aa\u7684\u6bd4\u4f8b\n        IF(YEAR(emp_hire_date) &lt; 1995)\n            THEN SET add_sal_rate = 1.2;\n        ELSEIF(YEAR(emp_hire_date) &lt;= 1998)\n            THEN SET add_sal_rate = 1.15;\n        ELSEIF(YEAR(emp_hire_date) &lt;= 2001)\n            THEN SET add_sal_rate = 1.10;\n        ELSE\n            SET add_sal_rate = 1.05;\n            END IF;\n\n        #\u6da8\u85aa\u64cd\u4f5c\n        UPDATE employees SET salary = salary * add_sal_rate\n        WHERE employee_id = emp_id;\n\n        #\u8fed\u4ee3\u6761\u4ef6\u7684\u66f4\u65b0\n        SET init_count = init_count + 1;\n\n    END WHILE;\n\n    #\u5173\u95ed\u6e38\u6807\n    CLOSE emp_cursor;\n\nEND $\n\nDELIMITER ;\n\n#\u8c03\u7528\n\nCALL update_salary(50,3);\n\nSELECT employee_id,hire_date,salary\nFROM employees\nWHERE department_id = 50\nORDER BY salary ASC;\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-1574","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\/1574"}],"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=1574"}],"version-history":[{"count":2,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1574\/revisions"}],"predecessor-version":[{"id":2673,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1574\/revisions\/2673"}],"wp:attachment":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1574"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1574"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1574"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}