{"id":175501,"date":"2024-11-08T06:24:20","date_gmt":"2024-11-07T22:24:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/175501\/"},"modified":"2024-11-08T06:24:20","modified_gmt":"2024-11-07T22:24:20","slug":"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%e4%be%86%e5%84%aa%e5%8c%96%e6%9f%a5%e8%a9%a2%ef%bc%88%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%e8%aa%bf%e7%94%a8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/175501\/","title":{"rendered":"\u5982\u4f55\u4f7f\u7528\u6578\u64da\u5eab\u51fd\u6578\u4f86\u512a\u5316\u67e5\u8a62\uff08\u6578\u64da\u5eab\u51fd\u6578\u8abf\u7528\uff09"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%e4%be%86%e5%84%aa%e5%8c%96%e6%9f%a5%e8%a9%a2%ef%bc%88%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%e8%aa%bf%e7%94%a8-hOiFnLICLU\">\u5982\u4f55\u4f7f\u7528\u6578\u64da\u5eab\u51fd\u6578\u4f86\u512a\u5316\u67e5\u8a62\uff08\u6578\u64da\u5eab\u51fd\u6578\u8abf\u7528\uff09<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0c\u6578\u64da\u5eab\u7684\u6027\u80fd\u5c0d\u65bc\u61c9\u7528\u7a0b\u5e8f\u7684\u6574\u9ad4\u6548\u7387\u81f3\u95dc\u91cd\u8981\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0c\u67e5\u8a62\u7684\u512a\u5316\u8b8a\u5f97\u6108\u52a0\u91cd\u8981\u3002\u4f7f\u7528\u6578\u64da\u5eab\u51fd\u6578\u662f\u4e00\u7a2e\u6709\u6548\u7684\u65b9\u5f0f\u4f86\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5982\u4f55\u5229\u7528\u6578\u64da\u5eab\u51fd\u6578\u4f86\u512a\u5316\u67e5\u8a62\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u793a\u4f8b\u548c\u5efa\u8b70\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%ef%bc%9f-hOiFnLICLU\">\u4ec0\u9ebc\u662f\u6578\u64da\u5eab\u51fd\u6578\uff1f<\/h2>\n<p>\u6578\u64da\u5eab\u51fd\u6578\u662f\u9810\u5b9a\u7fa9\u7684\u64cd\u4f5c\uff0c\u53ef\u4ee5\u5728\u67e5\u8a62\u4e2d\u8abf\u7528\uff0c\u4ee5\u57f7\u884c\u7279\u5b9a\u7684\u8a08\u7b97\u6216\u64cd\u4f5c\u3002\u9019\u4e9b\u51fd\u6578\u53ef\u4ee5\u662f\u5167\u5efa\u7684\uff0c\u4e5f\u53ef\u4ee5\u662f\u7528\u6236\u81ea\u5b9a\u7fa9\u7684\u3002\u5e38\u898b\u7684\u6578\u64da\u5eab\u51fd\u6578\u5305\u62ec\u805a\u5408\u51fd\u6578\uff08\u5982 <code>SUM()<\/code>\u3001<code>AVG()<\/code>\uff09\u3001\u5b57\u7b26\u4e32\u51fd\u6578\uff08\u5982 <code>CONCAT()<\/code>\u3001<code>SUBSTRING()<\/code>\uff09\u548c\u65e5\u671f\u51fd\u6578\uff08\u5982 <code>NOW()<\/code>\u3001<code>DATEDIFF()<\/code>\uff09\u7b49\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%e5%84%aa%e5%8c%96%e6%9f%a5%e8%a9%a2%e7%9a%84%e5%a5%bd%e8%99%95-hOiFnLICLU\">\u4f7f\u7528\u6578\u64da\u5eab\u51fd\u6578\u512a\u5316\u67e5\u8a62\u7684\u597d\u8655<\/h2>\n<ul>\n<li><strong>\u63d0\u9ad8\u6027\u80fd\uff1a<\/strong>\u901a\u904e\u5728\u6578\u64da\u5eab\u5c64\u9762\u9032\u884c\u8a08\u7b97\uff0c\u53ef\u4ee5\u6e1b\u5c11\u61c9\u7528\u7a0b\u5e8f\u5c64\u7684\u8ca0\u64d4\uff0c\u5f9e\u800c\u63d0\u9ad8\u6574\u9ad4\u6027\u80fd\u3002<\/li>\n<li><strong>\u7c21\u5316\u67e5\u8a62\uff1a<\/strong>\u4f7f\u7528\u51fd\u6578\u53ef\u4ee5\u4f7f\u67e5\u8a62\u8a9e\u53e5\u66f4\u7c21\u6f54\uff0c\u6613\u65bc\u7406\u89e3\u548c\u7dad\u8b77\u3002<\/li>\n<li><strong>\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\uff1a<\/strong>\u5728\u6578\u64da\u5eab\u4e2d\u9032\u884c\u8a08\u7b97\u53ef\u4ee5\u6e1b\u5c11\u9700\u8981\u50b3\u8f38\u5230\u61c9\u7528\u7a0b\u5e8f\u7684\u6578\u64da\u91cf\uff0c\u5f9e\u800c\u63d0\u9ad8\u6548\u7387\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%e5%84%aa%e5%8c%96%e6%9f%a5%e8%a9%a2-hOiFnLICLU\">\u5982\u4f55\u4f7f\u7528\u6578\u64da\u5eab\u51fd\u6578\u512a\u5316\u67e5\u8a62<\/h2>\n<h3 id=\"1-%e4%bd%bf%e7%94%a8%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8-hOiFnLICLU\">1. \u4f7f\u7528\u805a\u5408\u51fd\u6578<\/h3>\n<p>\u805a\u5408\u51fd\u6578\u53ef\u4ee5\u5728\u67e5\u8a62\u4e2d\u5feb\u901f\u8a08\u7b97\u7e3d\u548c\u3001\u5e73\u5747\u503c\u7b49\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>sales<\/code> \u7684\u8868\uff0c\u5305\u542b\u92b7\u552e\u6578\u64da\u3002\u6211\u5011\u53ef\u4ee5\u4f7f\u7528 <code>SUM()<\/code> \u51fd\u6578\u4f86\u8a08\u7b97\u7e3d\u92b7\u552e\u984d\uff1a<\/p>\n<pre><code>SELECT SUM(amount) AS total_sales FROM sales;<\/code><\/pre>\n<p>\u9019\u6a23\u7684\u67e5\u8a62\u53ef\u4ee5\u5feb\u901f\u8fd4\u56de\u7e3d\u92b7\u552e\u984d\uff0c\u800c\u4e0d\u9700\u8981\u5728\u61c9\u7528\u7a0b\u5e8f\u4e2d\u9032\u884c\u984d\u5916\u7684\u8a08\u7b97\u3002<\/p>\n<h3 id=\"2-%e4%bd%bf%e7%94%a8%e5%ad%97%e7%ac%a6%e4%b8%b2%e5%87%bd%e6%95%b8-hOiFnLICLU\">2. \u4f7f\u7528\u5b57\u7b26\u4e32\u51fd\u6578<\/h3>\n<p>\u5b57\u7b26\u4e32\u51fd\u6578\u53ef\u4ee5\u7528\u4f86\u8655\u7406\u548c\u683c\u5f0f\u5316\u6587\u672c\u6578\u64da\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u8981\u5c07\u7528\u6236\u7684\u540d\u5b57\u548c\u59d3\u6c0f\u5408\u4f75\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>CONCAT()<\/code> \u51fd\u6578\uff1a<\/p>\n<pre><code>SELECT CONCAT(first_name, ' ', last_name) AS full_name FROM users;<\/code><\/pre>\n<p>\u9019\u6a23\u53ef\u4ee5\u5728\u67e5\u8a62\u4e2d\u76f4\u63a5\u7372\u5f97\u5b8c\u6574\u7684\u59d3\u540d\uff0c\u800c\u4e0d\u9700\u8981\u5728\u61c9\u7528\u7a0b\u5e8f\u4e2d\u9032\u884c\u5b57\u7b26\u4e32\u62fc\u63a5\u3002<\/p>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8%e6%97%a5%e6%9c%9f%e5%87%bd%e6%95%b8-hOiFnLICLU\">3. \u4f7f\u7528\u65e5\u671f\u51fd\u6578<\/h3>\n<p>\u65e5\u671f\u51fd\u6578\u53ef\u4ee5\u7528\u4f86\u9032\u884c\u65e5\u671f\u8a08\u7b97\u548c\u683c\u5f0f\u5316\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u8981\u67e5\u8a62\u904e\u53bb30\u5929\u7684\u92b7\u552e\u6578\u64da\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>NOW()<\/code> \u548c <code>DATE_SUB()<\/code> \u51fd\u6578\uff1a<\/p>\n<pre><code>SELECT * FROM sales WHERE sale_date &gt; DATE_SUB(NOW(), INTERVAL 30 DAY);<\/code><\/pre>\n<p>\u9019\u6a23\u7684\u67e5\u8a62\u53ef\u4ee5\u5feb\u901f\u7372\u53d6\u6240\u9700\u7684\u6578\u64da\uff0c\u4e26\u4e14\u6613\u65bc\u7406\u89e3\u3002<\/p>\n<h3 id=\"4-%e5%89%b5%e5%bb%ba%e7%94%a8%e6%88%b6%e8%87%aa%e5%ae%9a%e7%be%a9%e5%87%bd%e6%95%b8-hOiFnLICLU\">4. \u5275\u5efa\u7528\u6236\u81ea\u5b9a\u7fa9\u51fd\u6578<\/h3>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u5167\u5efa\u7684\u6578\u64da\u5eab\u51fd\u6578\u53ef\u80fd\u7121\u6cd5\u6eff\u8db3\u7279\u5b9a\u9700\u6c42\u3002\u9019\u6642\uff0c\u53ef\u4ee5\u8003\u616e\u5275\u5efa\u7528\u6236\u81ea\u5b9a\u7fa9\u51fd\u6578\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u9700\u8981\u8a08\u7b97\u67d0\u500b\u6578\u5b57\u7684\u5e73\u65b9\u6839\uff0c\u53ef\u4ee5\u5275\u5efa\u4e00\u500b\u81ea\u5b9a\u7fa9\u51fd\u6578\uff1a<\/p>\n<pre><code>CREATE FUNCTION sqrt_custom(x DOUBLE) RETURNS DOUBLE\nBEGIN\n    RETURN SQRT(x);\nEND;<\/code><\/pre>\n<p>\u7136\u5f8c\u53ef\u4ee5\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528\u9019\u500b\u81ea\u5b9a\u7fa9\u51fd\u6578\uff1a<\/p>\n<pre><code>SELECT sqrt_custom(16) AS square_root;<\/code><\/pre>\n<h2 id=\"%e7%b5%90%e8%ab%96-hOiFnLICLU\">\u7d50\u8ad6<\/h2>\n<p>\u4f7f\u7528\u6578\u64da\u5eab\u51fd\u6578\u4f86\u512a\u5316\u67e5\u8a62\u662f\u4e00\u7a2e\u6709\u6548\u7684\u7b56\u7565\uff0c\u53ef\u4ee5\u63d0\u9ad8\u6027\u80fd\u3001\u7c21\u5316\u67e5\u8a62\u4e26\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u3002\u901a\u904e\u5408\u7406\u5229\u7528\u805a\u5408\u51fd\u6578\u3001\u5b57\u7b26\u4e32\u51fd\u6578\u3001\u65e5\u671f\u51fd\u6578\u4ee5\u53ca\u7528\u6236\u81ea\u5b9a\u7fa9\u51fd\u6578\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u986f\u8457\u63d0\u5347\u61c9\u7528\u7a0b\u5e8f\u7684\u6548\u7387\u3002\u5728\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u65b9\u6848\u6642\uff0c\u8003\u616e\u5230\u6578\u64da\u5eab\u6027\u80fd\u7684\u512a\u5316\uff0c\u5c07\u6709\u52a9\u65bc\u63d0\u5347\u6574\u9ad4\u7cfb\u7d71\u7684\u7a69\u5b9a\u6027\u548c\u97ff\u61c9\u901f\u5ea6\u3002\u4e86\u89e3\u66f4\u591a\u95dc\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u7684\u4fe1\u606f\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528\u6578\u64da\u5eab\u51fd\u6578\u4f86\u512a\u5316\u67e5\u8a62\u6027\u80fd\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u6548\u7387\uff0c\u5be6\u73fe\u66f4\u5feb\u7684\u6578\u64da\u6aa2\u7d22\u548c\u5206\u6790\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-175501","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/175501","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=175501"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/175501\/revisions"}],"predecessor-version":[{"id":175502,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/175501\/revisions\/175502"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=175501"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=175501"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=175501"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}