{"id":1559,"date":"2022-11-12T22:58:37","date_gmt":"2022-11-12T14:58:37","guid":{"rendered":"https:\/\/qaqaq.top\/?p=1559"},"modified":"2022-11-27T12:40:58","modified_gmt":"2022-11-27T04:40:58","slug":"%e6%95%b0%e6%8d%ae%e5%ba%93%e5%af%b9%e8%b1%a1%e4%b8%8e%e8%a7%86%e5%9b%be%e7%9a%84%e7%90%86%e8%a7%a3%e3%80%81%e8%a7%86%e5%9b%be%e7%9a%84%e5%88%9b%e5%bb%ba%e4%b8%8e%e6%9f%a5%e7%9c%8b%e3%80%81%e6%9b%b4","status":"publish","type":"post","link":"https:\/\/qaqaq.top\/?p=1559","title":{"rendered":"\u6570\u636e\u5e93\u5bf9\u8c61\u4e0e\u89c6\u56fe\u7684\u7406\u89e3\u3001\u89c6\u56fe\u7684\u521b\u5efa\u4e0e\u67e5\u770b\u3001\u66f4\u65b0\u89c6\u56fe\u6570\u636e\u4e0e\u89c6\u56fe\u7684\u5220\u9664"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code># \u7b2c14\u7ae0_\u89c6\u56fe(View)\r\n\r\n\/*\r\n 1. \u89c6\u56fe\u7684\u7406\u89e3\r\n\r\n \u2460 \u89c6\u56fe\uff0c\u53ef\u4ee5\u770b\u505a\u662f\u4e00\u4e2a\u865a\u62df\u8868\uff0c\u672c\u8eab\u662f\u4e0d\u5b58\u50a8\u6570\u636e\u7684\u3002\r\n    \u89c6\u56fe\u7684\u672c\u8d28\uff0c\u5c31\u53ef\u4ee5\u770b\u505a\u662f\u5b58\u50a8\u8d77\u6765\u7684SELECT\u8bed\u53e5\r\n\r\n \u2461 \u89c6\u56fe\u4e2dSELECT\u8bed\u53e5\u4e2d\u6d89\u53ca\u5230\u7684\u8868\uff0c\u79f0\u4e3a\u57fa\u8868\r\n\r\n \u2462 \u9488\u5bf9\u89c6\u56fe\u505aDML\u64cd\u4f5c\uff0c\u4f1a\u5f71\u54cd\u5230\u5bf9\u5e94\u7684\u57fa\u8868\u4e2d\u7684\u6570\u636e\u3002\u53cd\u4e4b\u4ea6\u7136\u3002\r\n\r\n \u2463 \u89c6\u56fe\u672c\u8eab\u7684\u5220\u9664\uff0c\u4e0d\u4f1a\u5bfc\u81f4\u57fa\u8868\u4e2d\u6570\u636e\u7684\u5220\u9664\u3002\r\n\r\n \u2464 \u89c6\u56fe\u7684\u5e94\u7528\u573a\u666f\uff1a\u9488\u5bf9\u4e8e\u5c0f\u578b\u9879\u76ee\uff0c\u4e0d\u63a8\u8350\u4f7f\u7528\u89c6\u56fe\u3002\u9488\u5bf9\u4e8e\u5927\u578b\u9879\u76ee\uff0c\u53ef\u4ee5\u8003\u8651\u4f7f\u7528\u89c6\u56fe\u3002\r\n\r\n \u2465 \u89c6\u56fe\u7684\u4f18\u70b9\uff1a\u7b80\u5316\u67e5\u8be2\uff1b\u63a7\u5236\u6570\u636e\u7684\u8bbf\u95ee\r\n\r\n *\/\r\n\r\n# 2. \u5982\u4f55\u521b\u5efa\u89c6\u56fe\r\n#\u51c6\u5907\u5de5\u4f5c\r\nCREATE DATABASE dbtest14;\r\n\r\nUSE dbtest14;\r\n\r\nCREATE TABLE emps\r\nAS\r\n    SELECT *\r\nFROM atguigudb.employees;\r\n\r\nCREATE TABLE depts\r\nAS\r\n    SELECT *\r\nFROM atguigudb.departments;\r\n\r\nSELECT * FROM emps;\r\n\r\nSELECT * FROM depts;\r\n\r\nDESC emps;\r\n\r\nDESC atguigudb.employees;\r\n\r\n# 2.1 \u9488\u5bf9\u4e8e\u5355\u8868\r\n#\u60c5\u51b51\uff1a\u89c6\u56fe\u4e2d\u7684\u5b57\u6bb5\u4e0e\u57fa\u8868\u7684\u5b57\u6bb5\u6709\u5bf9\u5e94\u5173\u7cfb\r\nCREATE VIEW vu_emp1\r\nAS\r\n    SELECT employee_id,last_name,salary\r\nFROM emps;\r\n\r\nSELECT * FROM vu_emp1;\r\n\r\n#\u786e\u5b9a\u89c6\u56fe\u4e2d\u5b57\u6bb5\u540d\u7684\u65b9\u5f0f1\uff1a\r\nCREATE VIEW vu_emp2\r\nAS\r\n    SELECT employee_id emp_id,last_name lname,salary    #\u67e5\u8be2\u8bed\u53e5\u4e2d\u5b57\u6bb5\u7684\u522b\u540d\u4f1a\u4f5c\u4e3a\u89c6\u56fe\u4e2d\u7684\u5b57\u6bb5\u7684\u540d\u79f0\u51fa\u73b0\r\nFROM emps\r\nWHERE salary > 8000;\r\n\r\n#\u786e\u5b9a\u89c6\u56fe\u4e2d\u5b57\u6bb5\u540d\u7684\u65b9\u5f0f2\uff1a\r\nCREATE VIEW vu_emp3(emp_id,name,monthly_sal)    #\u5c0f\u62ec\u53f7\u5185\u5b57\u6bb5\u4e2a\u6570\u4e8eSELECT\u4e2d\u5b57\u6bb5\u4e2a\u6570\u76f8\u540c\r\nAS\r\n    SELECT employee_id,last_name,salary\r\nFROM emps\r\nWHERE salary > 8000;\r\n\r\nSELECT * FROM vu_emp3;\r\n\r\n#\u60c5\u51b52\uff1a\u89c6\u56fe\u4e2d\u7684\u5b57\u6bb5\u5728\u57fa\u8868\u4e2d\u53ef\u80fd\u6ca1\u6709\u5bf9\u5e94\u7684\u5b57\u6bb5\r\nCREATE VIEW vu_emp_sal\r\nAS\r\nSELECT department_id,AVG(salary) avg_sal\r\nFROM emps\r\nWHERE department_id IS NOT NULL\r\nGROUP BY department_id;\r\n\r\nSELECT * FROM vu_emp_sal;\r\n\r\n#2.2 \u9488\u5bf9\u4e8e\u591a\u8868\r\n\r\nCREATE VIEW vu_emp_dept\r\nAS\r\nSELECT e.employee_id,e.department_id,d.department_name\r\nFROM emps e JOIN depts d\r\nON e.department_id = d.department_id;\r\n\r\nSELECT * FROM vu_emp_dept;\r\n\r\n#\u5229\u7528\u89c6\u56fe\u5bf9\u6570\u636e\u8fdb\u884c\u683c\u5f0f\u5316\r\n\r\nCREATE VIEW vu_emp_dept1\r\nAS\r\nSELECT CONCAT(e.last_name,'(',d.department_name,')') emp_info\r\nFROM emps e JOIN depts d\r\nON e.department_id = d.department_id;\r\n\r\nSELECT * FROM vu_emp_dept1;\r\n\r\n# 2.3 \u57fa\u4e8e\u89c6\u56fe\u521b\u5efa\u89c6\u56fe\r\n\r\nCREATE VIEW vu_emp4\r\nAS\r\n    SELECT employee_id,last_name\r\nFROM vu_emp1;\r\n\r\nSELECT * FROM vu_emp4;\r\n\r\n# 3. \u67e5\u770b\u89c6\u56fe\r\n# \u8bed\u6cd51\uff1a\u67e5\u770b\u6570\u636e\u5e93\u7684\u8868\u5bf9\u8c61\u3001\u89c6\u56fe\u5bf9\u8c61\r\nSHOW TABLES;\r\n\r\n# \u8bed\u6cd52\uff1a\u67e5\u770b\u89c6\u56fe\u7684\u7ed3\u6784\r\nDESCRIBE vu_emp1;\r\n\r\n# \u8bed\u6cd53\uff1a\u67e5\u770b\u89c6\u56fe\u7684\u5c5e\u6027\u4fe1\u606f\r\nSHOW TABLE STATUS LIKE 'vu_emp1';\r\n\r\n# \u8bed\u6cd54\uff1a\u67e5\u770b\u89c6\u56fe\u7684\u8be6\u7ec6\u5b9a\u4e49\u4fe1\u606f\r\nSHOW CREATE VIEW vu_emp1;\r\n\r\n# 4. \"\u66f4\u65b0\" \u89c6\u56fe\u4e2d\u7684\u6570\u636e\r\n# 4.1 \u4e00\u822c\u60c5\u51b5\uff0c\u53ef\u4ee5\u66f4\u65b0\u89c6\u56fe\u7684\u6570\u636e\r\nSELECT * FROM vu_emp1;\r\n\r\nSELECT employee_id,last_name,salary\r\nFROM emps;\r\n#\u66f4\u65b0\u89c6\u56fe\u7684\u6570\u636e\uff0c\u4f1a\u5bfc\u81f4\u57fa\u8868\u4e2d\u6570\u636e\u7684\u4fee\u6539\r\nUPDATE vu_emp1\r\nSET salary = 20000\r\nWHERE employee_id = 101;\r\n#\u540c\u7406\uff0c\u66f4\u65b0\u8868\u4e2d\u7684\u6570\u636e\uff0c\u4e5f\u4f1a\u5bfc\u81f4\u89c6\u56fe\u4e2d\u7684\u6570\u636e\u7684\u4fee\u6539\r\nUPDATE emps\r\nSET salary = 10000\r\nWHERE employee_id = 101;\r\n#\u5220\u9664\u89c6\u56fe\u4e2d\u7684\u6570\u636e\uff0c\u4e5f\u4f1a\u5bfc\u81f4\u8868\u4e2d\u7684\u6570\u636e\u7684\u5220\u9664\r\nDELETE FROM vu_emp1\r\nWHERE employee_id = 101;\r\n\r\nSELECT employee_id,last_name,salary\r\nFROM emps\r\nWHERE employee_id = 101;\r\n\r\n# 4.2 \u4e0d\u80fd\u66f4\u65b0\u89c6\u56fe\u4e2d\u7684\u6570\u636e\r\n\r\nSELECT * FROM vu_emp_sal;\r\n\r\n#\u66f4\u65b0\u5931\u8d25\r\nUPDATE vu_emp_sal\r\nSET avg_sal = 5000\r\nWHERE department_id = 30;\r\n\r\n#\u5220\u9664\u5931\u8d25\r\nDELETE FROM vu_emp_sal\r\nWHERE department_id = 30;\r\n\r\n# 5. \u4fee\u6539\u89c6\u56fe\r\n\r\nDESC vu_emp1;\r\n\r\n#\u65b9\u5f0f1\r\nCREATE OR REPLACE VIEW vu_emp1\r\nAS\r\n    SELECT employee_id,last_name,salary,email\r\nFROM emps\r\nWHERE salary > 7000;\r\n\r\n#\u65b9\u5f0f2\r\nALTER VIEW vu_emp1\r\nAS\r\n    SELECT employee_id,last_name,salary,email,hire_date\r\nFROM emps;\r\n\r\n# 6. \u5220\u9664\u89c6\u56fe\r\nSHOW TABLES;\r\n\r\nDROP VIEW vu_emp4;\r\n\r\nDROP VIEW IF EXISTS vu_emp2,vu_emp3;\r\n\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-1559","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\/1559"}],"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=1559"}],"version-history":[{"count":1,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1559\/revisions"}],"predecessor-version":[{"id":1560,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1559\/revisions\/1560"}],"wp:attachment":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1559"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1559"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1559"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}