{"id":196073,"date":"2024-11-13T20:17:20","date_gmt":"2024-11-13T12:17:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/196073\/"},"modified":"2024-11-13T20:17:21","modified_gmt":"2024-11-13T12:17:21","slug":"%e6%8e%8c%e6%8f%a1mysql-select%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%b7%a7%e5%a6%99%e6%96%b9%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/196073\/","title":{"rendered":"\u638c\u63e1MySQL SELECT\u8a9e\u53e5\u7684\u5de7\u5999\u65b9\u6cd5"},"content":{"rendered":"<h1 id=\"%e6%8e%8c%e6%8f%a1mysql-select%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%b7%a7%e5%a6%99%e6%96%b9%e6%b3%95-vCsUQHJNYy\">\u638c\u63e1MySQL SELECT\u8a9e\u53e5\u7684\u5de7\u5999\u65b9\u6cd5<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u7cfb\u7d71\uff0c\u800cSELECT\u8a9e\u53e5\u5247\u662f\u5176\u6700\u57fa\u672c\u4e14\u6700\u91cd\u8981\u7684\u67e5\u8a62\u8a9e\u53e5\u4e4b\u4e00\u3002\u7121\u8ad6\u662f\u5f9e\u6578\u64da\u5eab\u4e2d\u6aa2\u7d22\u6578\u64da\uff0c\u9084\u662f\u9032\u884c\u6578\u64da\u5206\u6790\uff0c\u638c\u63e1SELECT\u8a9e\u53e5\u7684\u4f7f\u7528\u6280\u5de7\u5c0d\u65bc\u958b\u767c\u8005\u548c\u6578\u64da\u5206\u6790\u5e2b\u4f86\u8aaa\u90fd\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u4e00\u4e9b\u5de7\u5999\u7684\u65b9\u6cd5\u4f86\u4f7f\u7528MySQL\u7684SELECT\u8a9e\u53e5\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u6709\u6548\u5730\u9032\u884c\u6578\u64da\u67e5\u8a62\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e7%9a%84select%e8%aa%9e%e5%8f%a5-vCsUQHJNYy\">\u57fa\u672c\u7684SELECT\u8a9e\u53e5<\/h2>\n<p>SELECT\u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT column1, column2, ...\nFROM table_name\nWHERE condition;<\/code><\/pre>\n<p>\u9019\u88e1\uff0ccolumn1\u3001column2\u662f\u8981\u6aa2\u7d22\u7684\u5217\u540d\uff0ctable_name\u662f\u6578\u64da\u8868\u7684\u540d\u7a31\uff0c\u800ccondition\u5247\u662f\u904e\u6ffe\u689d\u4ef6\u3002\u8209\u500b\u4f8b\u5b50\uff0c\u5982\u679c\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba\u201cemployees\u201d\u7684\u8868\uff0c\u60f3\u8981\u67e5\u8a62\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u8077\u4f4d\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u8a9e\u53e5\uff1a<\/p>\n<pre><code>SELECT name, position\nFROM employees;<\/code><\/pre>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e9%80%9a%e9%85%8d%e7%ac%a6%e9%80%b2%e8%a1%8c%e6%a8%a1%e7%b3%8a%e6%9f%a5%e8%a9%a2-vCsUQHJNYy\">\u4f7f\u7528\u901a\u914d\u7b26\u9032\u884c\u6a21\u7cca\u67e5\u8a62<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u6211\u5011\u53ef\u80fd\u53ea\u77e5\u9053\u90e8\u5206\u4fe1\u606f\uff0c\u9019\u6642\u53ef\u4ee5\u4f7f\u7528\u901a\u914d\u7b26\u9032\u884c\u6a21\u7cca\u67e5\u8a62\u3002MySQL\u652f\u6301\u5169\u7a2e\u901a\u914d\u7b26\uff1a\u767e\u5206\u865f\uff08%\uff09\u548c\u4e0b\u5283\u7dda\uff08_\uff09\u3002\u767e\u5206\u865f\u4ee3\u8868\u96f6\u500b\u6216\u591a\u500b\u5b57\u7b26\uff0c\u800c\u4e0b\u5283\u7dda\u4ee3\u8868\u55ae\u500b\u5b57\u7b26\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u67e5\u8a62\u6240\u6709\u4ee5\u201cJ\u201d\u958b\u982d\u7684\u54e1\u5de5\u59d3\u540d\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT name\nFROM employees\nWHERE name LIKE 'J%';<\/code><\/pre>\n<h2 id=\"%e6%8e%92%e5%ba%8f%e5%92%8c%e9%99%90%e5%88%b6%e7%b5%90%e6%9e%9c-vCsUQHJNYy\">\u6392\u5e8f\u548c\u9650\u5236\u7d50\u679c<\/h2>\n<p>\u5728\u67e5\u8a62\u7d50\u679c\u4e2d\uff0c\u7d93\u5e38\u9700\u8981\u5c0d\u6578\u64da\u9032\u884c\u6392\u5e8f\u3002\u53ef\u4ee5\u4f7f\u7528ORDER BY\u5b50\u53e5\u4f86\u5be6\u73fe\uff0c\u4e26\u4e14\u53ef\u4ee5\u6307\u5b9a\u5347\u5e8f\uff08ASC\uff09\u6216\u964d\u5e8f\uff08DESC\uff09\u3002\u6b64\u5916\uff0cLIMIT\u5b50\u53e5\u53ef\u4ee5\u7528\u4f86\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u82e5\u8981\u67e5\u8a62\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\uff0c\u4e26\u6309\u5e74\u9f61\u964d\u5e8f\u6392\u5217\uff0c\u53ea\u986f\u793a\u524d10\u540d\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u8a9e\u53e5\uff1a<\/p>\n<pre><code>SELECT name\nFROM employees\nORDER BY age DESC\nLIMIT 10;<\/code><\/pre>\n<h2 id=\"%e8%81%af%e6%8e%a5%e5%a4%9a%e5%80%8b%e8%a1%a8-vCsUQHJNYy\">\u806f\u63a5\u591a\u500b\u8868<\/h2>\n<p>\u5728\u5be6\u969b\u61c9\u7528\u4e2d\uff0c\u6578\u64da\u901a\u5e38\u5206\u6563\u5728\u591a\u500b\u8868\u4e2d\u3002\u4f7f\u7528JOIN\u8a9e\u53e5\u53ef\u4ee5\u5c07\u9019\u4e9b\u8868\u806f\u63a5\u8d77\u4f86\uff0c\u5f9e\u800c\u9032\u884c\u66f4\u8907\u96dc\u7684\u67e5\u8a62\u3002MySQL\u652f\u6301\u591a\u7a2e\u806f\u63a5\u65b9\u5f0f\uff0c\u5305\u62ecINNER JOIN\u3001LEFT JOIN\u548cRIGHT JOIN\u7b49\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u201cdepartments\u201d\u8868\uff0c\u60f3\u8981\u67e5\u8a62\u6bcf\u4f4d\u54e1\u5de5\u53ca\u5176\u6240\u5c6c\u90e8\u9580\u7684\u540d\u7a31\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT employees.name, departments.department_name\nFROM employees\nINNER JOIN departments ON employees.department_id = departments.id;<\/code><\/pre>\n<h2 id=\"%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8%e7%9a%84%e4%bd%bf%e7%94%a8-vCsUQHJNYy\">\u805a\u5408\u51fd\u6578\u7684\u4f7f\u7528<\/h2>\n<p>MySQL\u9084\u63d0\u4f9b\u4e86\u591a\u7a2e\u805a\u5408\u51fd\u6578\uff0c\u5982COUNT\u3001SUM\u3001AVG\u3001MAX\u548cMIN\u7b49\uff0c\u9019\u4e9b\u51fd\u6578\u53ef\u4ee5\u7528\u4f86\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u7d71\u8a08\u5206\u6790\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u8981\u8a08\u7b97\u6bcf\u500b\u90e8\u9580\u7684\u54e1\u5de5\u6578\u91cf\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u8a9e\u53e5\uff1a<\/p>\n<pre><code>SELECT department_id, COUNT(*)\nFROM employees\nGROUP BY department_id;<\/code><\/pre>\n<h2 id=\"%e5%b0%8f%e7%b5%90-vCsUQHJNYy\">\u5c0f\u7d50<\/h2>\n<p>\u638c\u63e1MySQL\u7684SELECT\u8a9e\u53e5\u53ca\u5176\u5404\u7a2e\u7528\u6cd5\uff0c\u53ef\u4ee5\u5927\u5927\u63d0\u9ad8\u6578\u64da\u67e5\u8a62\u7684\u6548\u7387\u548c\u9748\u6d3b\u6027\u3002\u7121\u8ad6\u662f\u57fa\u672c\u67e5\u8a62\u3001\u6a21\u7cca\u67e5\u8a62\u3001\u6392\u5e8f\u3001\u806f\u63a5\u9084\u662f\u805a\u5408\u51fd\u6578\uff0c\u9019\u4e9b\u6280\u5de7\u90fd\u80fd\u5e6b\u52a9\u958b\u767c\u8005\u548c\u6578\u64da\u5206\u6790\u5e2b\u66f4\u597d\u5730\u8655\u7406\u6578\u64da\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u5982\u4f55\u5728\u96f2\u7aef\u74b0\u5883\u4e2d\u904b\u884cMySQL\u6709\u8208\u8da3\uff0c\u6216\u8005\u60f3\u8981\u4e86\u89e3\u66f4\u591a\u95dc\u65bc<code><a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a><\/code>\u7684\u8cc7\u8a0a\uff0c\u8acb\u96a8\u6642\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8cc7\u6e90\u548c\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u638c\u63e1MySQL SELECT\u8a9e\u53e5\u7684\u5de7\u5999\u65b9\u6cd5\uff0c\u63d0\u5347\u6578\u64da\u67e5\u8a62\u6548\u7387\uff0c\u5b78\u7fd2\u6700\u4f73\u5be6\u8e10\uff0c\u8b93\u4f60\u7684\u6578\u64da\u64cd\u4f5c\u66f4\u7c21\u55ae\u9ad8\u6548\u3002<\/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-196073","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/196073","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=196073"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/196073\/revisions"}],"predecessor-version":[{"id":196074,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/196073\/revisions\/196074"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=196073"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=196073"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=196073"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}