{"id":187418,"date":"2024-11-11T14:06:20","date_gmt":"2024-11-11T06:06:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/187418\/"},"modified":"2024-11-11T14:06:21","modified_gmt":"2024-11-11T06:06:21","slug":"%e6%95%b8%e6%93%9a%e5%ba%ab%e7%b3%bb%e7%b5%b1%e5%87%bd%e6%95%b8%e7%b0%a1%e4%bb%8b-%e6%95%b8%e6%93%9a%e5%ba%ab%e7%9a%84%e7%b3%bb%e7%b5%b1%e5%87%bd%e6%95%b8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/187418\/","title":{"rendered":"\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u7c21\u4ecb (\u6578\u64da\u5eab\u7684\u7cfb\u7d71\u51fd\u6578)"},"content":{"rendered":"<h1 id=\"%e6%95%b8%e6%93%9a%e5%ba%ab%e7%b3%bb%e7%b5%b1%e5%87%bd%e6%95%b8%e7%b0%a1%e4%bb%8b-%e6%95%b8%e6%93%9a%e5%ba%ab%e7%9a%84%e7%b3%bb%e7%b5%b1%e5%87%bd%e6%95%b8-LgjlZmgtav\">\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u7c21\u4ecb (\u6578\u64da\u5eab\u7684\u7cfb\u7d71\u51fd\u6578)<\/h1>\n<p>\u5728\u73fe\u4ee3\u7684\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u7cfb\u7d71\u51fd\u6578\u626e\u6f14\u8457\u81f3\u95dc\u91cd\u8981\u7684\u89d2\u8272\u3002\u9019\u4e9b\u51fd\u6578\u4e0d\u50c5\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u9032\u884c\u6578\u64da\u64cd\u4f5c\uff0c\u9084\u80fd\u63d0\u9ad8\u6578\u64da\u8655\u7406\u7684\u6548\u7387\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u7684\u57fa\u672c\u6982\u5ff5\u3001\u985e\u578b\u53ca\u5176\u61c9\u7528\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u9019\u4e00\u4e3b\u984c\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e6%95%b8%e6%93%9a%e5%ba%ab%e7%b3%bb%e7%b5%b1%e5%87%bd%e6%95%b8%ef%bc%9f-LgjlZmgtav\">\u4ec0\u9ebc\u662f\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\uff1f<\/h2>\n<p>\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u662f\u6307\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\u9810\u5b9a\u7fa9\u7684\u51fd\u6578\uff0c\u9019\u4e9b\u51fd\u6578\u53ef\u4ee5\u7528\u4f86\u57f7\u884c\u7279\u5b9a\u7684\u64cd\u4f5c\uff0c\u5982\u6578\u64da\u67e5\u8a62\u3001\u6578\u64da\u66f4\u65b0\u3001\u6578\u64da\u8a08\u7b97\u7b49\u3002\u9019\u4e9b\u51fd\u6578\u901a\u5e38\u662f\u7528\u65bc SQL \u8a9e\u8a00\u4e2d\uff0c\u4e26\u4e14\u53ef\u4ee5\u5728\u67e5\u8a62\u4e2d\u76f4\u63a5\u8abf\u7528\u3002<\/p>\n<h2 id=\"%e6%95%b8%e6%93%9a%e5%ba%ab%e7%b3%bb%e7%b5%b1%e5%87%bd%e6%95%b8%e7%9a%84%e9%a1%9e%e5%9e%8b-LgjlZmgtav\">\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u7684\u985e\u578b<\/h2>\n<p>\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u53ef\u4ee5\u6839\u64da\u5176\u529f\u80fd\u7684\u4e0d\u540c\u5206\u70ba\u5e7e\u500b\u4e3b\u8981\u985e\u578b\uff1a<\/p>\n<ul>\n<li><strong>\u805a\u5408\u51fd\u6578\uff1a<\/strong>\u9019\u985e\u51fd\u6578\u7528\u65bc\u5c0d\u4e00\u7d44\u503c\u9032\u884c\u8a08\u7b97\uff0c\u4e26\u8fd4\u56de\u55ae\u4e00\u7684\u7d50\u679c\u3002\u4f8b\u5982\uff0c<code>SUM()<\/code>\u3001<code>AVG()<\/code>\u3001<code>COUNT()<\/code>\u7b49\u3002<\/li>\n<li><strong>\u5b57\u7b26\u4e32\u51fd\u6578\uff1a<\/strong>\u9019\u4e9b\u51fd\u6578\u7528\u65bc\u8655\u7406\u5b57\u7b26\u4e32\u6578\u64da\uff0c\u5982<code>CONCAT()<\/code>\u3001<code>SUBSTRING()<\/code>\u3001<code>UPPER()<\/code>\u7b49\u3002<\/li>\n<li><strong>\u6578\u5b78\u51fd\u6578\uff1a<\/strong>\u7528\u65bc\u57f7\u884c\u6578\u5b78\u8a08\u7b97\u7684\u51fd\u6578\uff0c\u4f8b\u5982<code>ROUND()<\/code>\u3001<code>FLOOR()<\/code>\u3001<code>CEIL()<\/code>\u7b49\u3002<\/li>\n<li><strong>\u65e5\u671f\u548c\u6642\u9593\u51fd\u6578\uff1a<\/strong>\u9019\u985e\u51fd\u6578\u7528\u65bc\u8655\u7406\u65e5\u671f\u548c\u6642\u9593\u6578\u64da\uff0c\u5982<code>NOW()<\/code>\u3001<code>DATEADD()<\/code>\u3001<code>DATEDIFF()<\/code>\u7b49\u3002<\/li>\n<li><strong>\u8f49\u63db\u51fd\u6578\uff1a<\/strong>\u9019\u4e9b\u51fd\u6578\u7528\u65bc\u6578\u64da\u985e\u578b\u4e4b\u9593\u7684\u8f49\u63db\uff0c\u4f8b\u5982<code>CAST()<\/code>\u548c<code>CONVERT()<\/code>\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b3%bb%e7%b5%b1%e5%87%bd%e6%95%b8%e7%9a%84%e6%87%89%e7%94%a8%e7%a4%ba%e4%be%8b-LgjlZmgtav\">\u7cfb\u7d71\u51fd\u6578\u7684\u61c9\u7528\u793a\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5e38\u898b\u7684\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u7684\u61c9\u7528\u793a\u4f8b\uff1a<\/p>\n<h3 id=\"1-%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8%e7%a4%ba%e4%be%8b-LgjlZmgtav\">1. \u805a\u5408\u51fd\u6578\u793a\u4f8b<\/h3>\n<pre><code>\nSELECT COUNT(*) AS total_users FROM users;\n<\/code><\/pre>\n<p>\u4e0a\u8ff0\u67e5\u8a62\u5c07\u8fd4\u56de\u7528\u6236\u8868\u4e2d\u7684\u7e3d\u7528\u6236\u6578\u3002<\/p>\n<h3 id=\"2-%e5%ad%97%e7%ac%a6%e4%b8%b2%e5%87%bd%e6%95%b8%e7%a4%ba%e4%be%8b-LgjlZmgtav\">2. \u5b57\u7b26\u4e32\u51fd\u6578\u793a\u4f8b<\/h3>\n<pre><code>\nSELECT CONCAT(first_name, ' ', last_name) AS full_name FROM employees;\n<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u54e1\u5de5\u7684\u5168\u540d\uff0c\u901a\u904e\u5c07\u540d\u5b57\u548c\u59d3\u6c0f\u9023\u63a5\u8d77\u4f86\u3002<\/p>\n<h3 id=\"3-%e6%95%b8%e5%ad%b8%e5%87%bd%e6%95%b8%e7%a4%ba%e4%be%8b-LgjlZmgtav\">3. \u6578\u5b78\u51fd\u6578\u793a\u4f8b<\/h3>\n<pre><code>\nSELECT ROUND(price, 2) AS rounded_price FROM products;\n<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u7522\u54c1\u50f9\u683c\u7684\u56db\u6368\u4e94\u5165\u503c\uff0c\u4fdd\u7559\u5169\u4f4d\u5c0f\u6578\u3002<\/p>\n<h3 id=\"4-%e6%97%a5%e6%9c%9f%e5%92%8c%e6%99%82%e9%96%93%e5%87%bd%e6%95%b8%e7%a4%ba%e4%be%8b-LgjlZmgtav\">4. \u65e5\u671f\u548c\u6642\u9593\u51fd\u6578\u793a\u4f8b<\/h3>\n<pre><code>\nSELECT DATEDIFF(NOW(), hire_date) AS days_since_hired FROM employees;\n<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8a08\u7b97\u81ea\u54e1\u5de5\u5165\u8077\u4ee5\u4f86\u7684\u5929\u6578\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-LgjlZmgtav\">\u7d50\u8ad6<\/h2>\n<p>\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u662f\u6578\u64da\u5eab\u64cd\u4f5c\u4e2d\u4e0d\u53ef\u6216\u7f3a\u7684\u4e00\u90e8\u5206\uff0c\u901a\u904e\u4f7f\u7528\u9019\u4e9b\u51fd\u6578\uff0c\u958b\u767c\u8005\u548c\u6578\u64da\u5206\u6790\u5e2b\u53ef\u4ee5\u66f4\u9ad8\u6548\u5730\u8655\u7406\u548c\u5206\u6790\u6578\u64da\u3002\u4e86\u89e3\u9019\u4e9b\u51fd\u6578\u7684\u4f7f\u7528\u65b9\u6cd5\u548c\u61c9\u7528\u5834\u666f\uff0c\u5c07\u6709\u52a9\u65bc\u63d0\u5347\u6578\u64da\u5eab\u64cd\u4f5c\u7684\u6548\u7387\u548c\u6e96\u78ba\u6027\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7ba1\u7406\u6709\u9032\u4e00\u6b65\u7684\u9700\u6c42\uff0c\u7121\u8ad6\u662f\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0c\u9084\u662f\u9700\u8981\u7a69\u5b9a\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u670d\u52d9\uff0cServer.HK \u90fd\u80fd\u63d0\u4f9b\u5c08\u696d\u7684\u652f\u6301\u548c\u670d\u52d9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3\u6578\u64da\u5eab\u7cfb\u7d71\u51fd\u6578\u7684\u57fa\u672c\u6982\u5ff5\uff0c\u63a2\u7d22\u5176\u5728\u6578\u64da\u7ba1\u7406\u548c\u67e5\u8a62\u4e2d\u7684\u61c9\u7528\uff0c\u63d0\u5347\u6578\u64da\u5eab\u64cd\u4f5c\u6548\u7387\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-187418","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187418","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=187418"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187418\/revisions"}],"predecessor-version":[{"id":187419,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187418\/revisions\/187419"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=187418"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=187418"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=187418"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}