{"id":76412,"date":"2024-10-16T06:27:15","date_gmt":"2024-10-15T22:27:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/76412\/"},"modified":"2024-10-16T06:27:15","modified_gmt":"2024-10-15T22:27:15","slug":"mysql%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e6%89%be%e7%b7%b4%e7%bf%92%e9%a1%8c%ef%bc%8c%e8%bc%95%e9%ac%86%e6%8e%8c%e6%8f%a1%e6%9f%a5%e8%a9%a2%e6%8a%80%e5%b7%a7%ef%bc%81-mysql%e6%95%b8%e6%93%9a","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/76412\/","title":{"rendered":"MySQL\u6578\u64da\u5eab\u67e5\u627e\u7df4\u7fd2\u984c\uff0c\u8f15\u9b06\u638c\u63e1\u67e5\u8a62\u6280\u5de7\uff01 (MySQL\u6578\u64da\u5eab\u67e5\u627e\u984c)"},"content":{"rendered":"<h1 id=\"mysql%e6%95%b8%e6%93%9a%e5%ba%ab%e6%9f%a5%e6%89%be%e7%b7%b4%e7%bf%92%e9%a1%8c%ef%bc%8c%e8%bc%95%e9%ac%86%e6%8e%8c%e6%8f%a1%e6%9f%a5%e8%a9%a2%e6%8a%80%e5%b7%a7%ef%bc%81-MlcOZVotND\">MySQL\u6578\u64da\u5eab\u67e5\u627e\u7df4\u7fd2\u984c\uff0c\u8f15\u9b06\u638c\u63e1\u67e5\u8a62\u6280\u5de7\uff01<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0cMySQL\u4f5c\u70ba\u4e00\u7a2e\u6d41\u884c\u7684\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u5ee3\u6cdb\u61c9\u7528\u65bc\u5404\u7a2e\u61c9\u7528\u7a0b\u5e8f\u4e2d\u3002\u638c\u63e1MySQL\u7684\u67e5\u8a62\u6280\u5de7\u5c0d\u65bc\u6578\u64da\u5206\u6790\u548c\u61c9\u7528\u958b\u767c\u81f3\u95dc\u91cd\u8981\u3002\u672c\u6587\u5c07\u901a\u904e\u4e00\u4e9b\u7df4\u7fd2\u984c\u4f86\u5e6b\u52a9\u8b80\u8005\u8f15\u9b06\u638c\u63e1MySQL\u7684\u67e5\u8a62\u6280\u5de7\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e6%9f%a5%e8%a9%a2-MlcOZVotND\">\u57fa\u672c\u67e5\u8a62<\/h2>\n<p>\u9996\u5148\uff0c\u6211\u5011\u4f86\u770b\u770b\u6700\u57fa\u672c\u7684\u67e5\u8a62\u8a9e\u53e5\u3002\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba\u201cemployees\u201d\u7684\u8868\uff0c\u7d50\u69cb\u5982\u4e0b\uff1a<\/p>\n<pre>\nCREATE TABLE employees (\n    id INT AUTO_INCREMENT PRIMARY KEY,\n    name VARCHAR(100),\n    position VARCHAR(100),\n    salary DECIMAL(10, 2)\n);\n<\/pre>\n<p>\u8981\u67e5\u8a62\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u8077\u4f4d\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0bSQL\u8a9e\u53e5\uff1a<\/p>\n<pre>\nSELECT name, position FROM employees;\n<\/pre>\n<h2 id=\"%e6%a2%9d%e4%bb%b6%e6%9f%a5%e8%a9%a2-MlcOZVotND\">\u689d\u4ef6\u67e5\u8a62<\/h2>\n<p>\u5728\u5be6\u969b\u61c9\u7528\u4e2d\uff0c\u6211\u5011\u7d93\u5e38\u9700\u8981\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u4f86\u7be9\u9078\u6578\u64da\u3002\u5047\u8a2d\u6211\u5011\u60f3\u67e5\u8a62\u85aa\u6c34\u9ad8\u65bc50000\u7684\u54e1\u5de5\uff0c\u53ef\u4ee5\u4f7f\u7528WHERE\u5b50\u53e5\uff1a<\/p>\n<pre>\nSELECT * FROM employees WHERE salary &gt; 50000;\n<\/pre>\n<h2 id=\"%e6%8e%92%e5%ba%8f%e6%9f%a5%e8%a9%a2-MlcOZVotND\">\u6392\u5e8f\u67e5\u8a62<\/h2>\n<p>\u6709\u6642\u5019\uff0c\u6211\u5011\u9700\u8981\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u6392\u5e8f\u3002\u5047\u8a2d\u6211\u5011\u60f3\u6309\u85aa\u6c34\u5f9e\u9ad8\u5230\u4f4e\u6392\u5e8f\uff0c\u53ef\u4ee5\u4f7f\u7528ORDER BY\u5b50\u53e5\uff1a<\/p>\n<pre>\nSELECT * FROM employees ORDER BY salary DESC;\n<\/pre>\n<h2 id=\"%e5%88%86%e7%b5%84%e6%9f%a5%e8%a9%a2-MlcOZVotND\">\u5206\u7d44\u67e5\u8a62<\/h2>\n<p>\u5982\u679c\u6211\u5011\u60f3\u8981\u6839\u64da\u8077\u4f4d\u4f86\u7d71\u8a08\u6bcf\u500b\u8077\u4f4d\u7684\u54e1\u5de5\u6578\u91cf\uff0c\u53ef\u4ee5\u4f7f\u7528GROUP BY\u5b50\u53e5\uff1a<\/p>\n<pre>\nSELECT position, COUNT(*) AS num_employees FROM employees GROUP BY position;\n<\/pre>\n<h2 id=\"%e8%81%af%e6%8e%a5%e6%9f%a5%e8%a9%a2-MlcOZVotND\">\u806f\u63a5\u67e5\u8a62<\/h2>\n<p>\u5728\u591a\u500b\u8868\u4e4b\u9593\u9032\u884c\u67e5\u8a62\u6642\uff0c\u806f\u63a5\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u5047\u8a2d\u6211\u5011\u6709\u53e6\u4e00\u500b\u540d\u70ba\u201cdepartments\u201d\u7684\u8868\uff0c\u7d50\u69cb\u5982\u4e0b\uff1a<\/p>\n<pre>\nCREATE TABLE departments (\n    id INT AUTO_INCREMENT PRIMARY KEY,\n    department_name VARCHAR(100)\n);\n<\/pre>\n<p>\u5982\u679c\u6211\u5011\u60f3\u67e5\u8a62\u6bcf\u500b\u54e1\u5de5\u53ca\u5176\u6240\u5c6c\u90e8\u9580\u7684\u540d\u7a31\uff0c\u53ef\u4ee5\u4f7f\u7528INNER JOIN\uff1a<\/p>\n<pre>\nSELECT employees.name, departments.department_name \nFROM employees \nINNER JOIN departments ON employees.department_id = departments.id;\n<\/pre>\n<h2 id=\"%e5%ad%90%e6%9f%a5%e8%a9%a2-MlcOZVotND\">\u5b50\u67e5\u8a62<\/h2>\n<p>\u5b50\u67e5\u8a62\u662f\u4e00\u7a2e\u5728\u67e5\u8a62\u4e2d\u5d4c\u5957\u53e6\u4e00\u500b\u67e5\u8a62\u7684\u6280\u8853\u3002\u5047\u8a2d\u6211\u5011\u60f3\u67e5\u8a62\u85aa\u6c34\u9ad8\u65bc\u6240\u6709\u90e8\u9580\u5e73\u5747\u85aa\u6c34\u7684\u54e1\u5de5\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre>\nSELECT * FROM employees \nWHERE salary &gt; (SELECT AVG(salary) FROM employees);\n<\/pre>\n<h2 id=\"%e7%b7%b4%e7%bf%92%e9%a1%8c-MlcOZVotND\">\u7df4\u7fd2\u984c<\/h2>\n<p>\u70ba\u4e86\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u638c\u63e1\u67e5\u8a62\u6280\u5de7\uff0c\u4ee5\u4e0b\u662f\u5e7e\u500b\u7df4\u7fd2\u984c\uff1a<\/p>\n<ul>\n<li>\u67e5\u8a62\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u85aa\u6c34\uff0c\u4e26\u6309\u85aa\u6c34\u5f9e\u4f4e\u5230\u9ad8\u6392\u5e8f\u3002<\/li>\n<li>\u67e5\u8a62\u6240\u6709\u8077\u4f4d\u70ba\u201c\u7d93\u7406\u201d\u7684\u54e1\u5de5\u3002<\/li>\n<li>\u67e5\u8a62\u6bcf\u500b\u90e8\u9580\u7684\u6700\u9ad8\u85aa\u6c34\u3002<\/li>\n<li>\u67e5\u8a62\u85aa\u6c34\u572830000\u523060000\u4e4b\u9593\u7684\u54e1\u5de5\u59d3\u540d\u548c\u8077\u4f4d\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-MlcOZVotND\">\u7e3d\u7d50<\/h2>\n<p>\u901a\u904e\u4ee5\u4e0a\u7684\u7df4\u7fd2\u984c\u548c\u793a\u4f8b\uff0c\u8b80\u8005\u61c9\u8a72\u80fd\u5920\u638c\u63e1MySQL\u7684\u57fa\u672c\u67e5\u8a62\u6280\u5de7\u3002\u9019\u4e9b\u6280\u5de7\u4e0d\u50c5\u80fd\u5e6b\u52a9\u4f60\u5728\u65e5\u5e38\u5de5\u4f5c\u4e2d\u66f4\u6709\u6548\u5730\u8655\u7406\u6578\u64da\uff0c\u9084\u80fd\u70ba\u672a\u4f86\u7684\u6578\u64da\u5206\u6790\u6253\u4e0b\u5805\u5be6\u7684\u57fa\u790e\u3002\u5982\u679c\u4f60\u9700\u8981\u66f4\u9ad8\u6548\u7684\u6578\u64da\u5b58\u5132\u548c\u7ba1\u7406\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216<a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a>\u4f86\u652f\u6301\u4f60\u7684\u61c9\u7528\u7a0b\u5e8f\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u638c\u63e1MySQL\u6578\u64da\u5eab\u67e5\u8a62\u6280\u5de7\uff0c\u901a\u904e\u7df4\u7fd2\u984c\u8f15\u9b06\u63d0\u5347\u67e5\u627e\u80fd\u529b\uff0c\u9069\u5408\u521d\u5b78\u8005\u548c\u9032\u968e\u7528\u6236\uff01<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-76412","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76412","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=76412"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76412\/revisions"}],"predecessor-version":[{"id":76413,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76412\/revisions\/76413"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=76412"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=76412"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=76412"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}