{"id":143915,"date":"2024-11-01T02:19:18","date_gmt":"2024-10-31T18:19:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/143915\/"},"modified":"2024-11-01T02:19:19","modified_gmt":"2024-10-31T18:19:19","slug":"sql-%e6%95%b8%e6%93%9a%e5%ba%ab%ef%bc%9a%e8%81%9a%e9%9b%86%e5%87%bd%e6%95%b8%e4%b9%8b%e5%b7%ae-%e6%95%b8%e6%93%9a%e5%ba%ab%e8%81%9a%e9%9b%86%e5%87%bd%e6%95%b8%e7%9b%b8%e6%b8%9b","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/143915\/","title":{"rendered":"SQL \u6578\u64da\u5eab\uff1a\u805a\u96c6\u51fd\u6578\u4e4b\u5dee (\u6578\u64da\u5eab\u805a\u96c6\u51fd\u6578\u76f8\u6e1b)"},"content":{"rendered":"<h1 id=\"sql-%e6%95%b8%e6%93%9a%e5%ba%ab%ef%bc%9a%e8%81%9a%e9%9b%86%e5%87%bd%e6%95%b8%e4%b9%8b%e5%b7%ae-%e6%95%b8%e6%93%9a%e5%ba%ab%e8%81%9a%e9%9b%86%e5%87%bd%e6%95%b8%e7%9b%b8%e6%b8%9b-RDrdBlLEby\">SQL \u6578\u64da\u5eab\uff1a\u805a\u96c6\u51fd\u6578\u4e4b\u5dee (\u6578\u64da\u5eab\u805a\u96c6\u51fd\u6578\u76f8\u6e1b)<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u805a\u96c6\u51fd\u6578\u662f\u7528\u4f86\u5c0d\u4e00\u7d44\u6578\u64da\u9032\u884c\u8a08\u7b97\u4e26\u8fd4\u56de\u55ae\u4e00\u503c\u7684\u51fd\u6578\u3002\u9019\u4e9b\u51fd\u6578\u5728\u6578\u64da\u5206\u6790\u548c\u5831\u544a\u4e2d\u626e\u6f14\u8457\u91cd\u8981\u7684\u89d2\u8272\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u805a\u96c6\u51fd\u6578\u7684\u57fa\u672c\u6982\u5ff5\uff0c\u4e26\u6df1\u5165\u5206\u6790\u5982\u4f55\u9032\u884c\u805a\u96c6\u51fd\u6578\u4e4b\u9593\u7684\u76f8\u6e1b\u64cd\u4f5c\u3002<\/p>\n<h2 id=\"%e8%81%9a%e9%9b%86%e5%87%bd%e6%95%b8%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-RDrdBlLEby\">\u805a\u96c6\u51fd\u6578\u7684\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>\u805a\u96c6\u51fd\u6578\u901a\u5e38\u7528\u65bc SQL \u67e5\u8a62\u4e2d\uff0c\u5e38\u898b\u7684\u805a\u96c6\u51fd\u6578\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><code>COUNT()<\/code>\uff1a\u8a08\u7b97\u884c\u6578\u3002<\/li>\n<li><code>SUM()<\/code>\uff1a\u8a08\u7b97\u6578\u503c\u7684\u7e3d\u548c\u3002<\/li>\n<li><code>AVG()<\/code>\uff1a\u8a08\u7b97\u6578\u503c\u7684\u5e73\u5747\u503c\u3002<\/li>\n<li><code>MIN()<\/code>\uff1a\u627e\u51fa\u6700\u5c0f\u503c\u3002<\/li>\n<li><code>MAX()<\/code>\uff1a\u627e\u51fa\u6700\u5927\u503c\u3002<\/li>\n<\/ul>\n<p>\u9019\u4e9b\u51fd\u6578\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u5feb\u901f\u7372\u53d6\u6578\u64da\u7684\u7d71\u8a08\u4fe1\u606f\uff0c\u5f9e\u800c\u9032\u884c\u66f4\u6df1\u5165\u7684\u5206\u6790\u3002<\/p>\n<h2 id=\"%e8%81%9a%e9%9b%86%e5%87%bd%e6%95%b8%e7%9b%b8%e6%b8%9b%e7%9a%84%e6%a6%82%e5%bf%b5-RDrdBlLEby\">\u805a\u96c6\u51fd\u6578\u76f8\u6e1b\u7684\u6982\u5ff5<\/h2>\n<p>\u805a\u96c6\u51fd\u6578\u76f8\u6e1b\u7684\u64cd\u4f5c\u901a\u5e38\u7528\u65bc\u6bd4\u8f03\u4e0d\u540c\u6578\u64da\u96c6\u4e4b\u9593\u7684\u5dee\u7570\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u5169\u500b\u4e0d\u540c\u6642\u9593\u6bb5\u7684\u92b7\u552e\u6578\u64da\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528\u805a\u96c6\u51fd\u6578\u4f86\u8a08\u7b97\u6bcf\u500b\u6642\u9593\u6bb5\u7684\u7e3d\u92b7\u552e\u984d\uff0c\u7136\u5f8c\u9032\u884c\u76f8\u6e1b\u4ee5\u7372\u5f97\u92b7\u552e\u984d\u7684\u8b8a\u5316\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b%ef%bc%9a%e8%a8%88%e7%ae%97%e9%8a%b7%e5%94%ae%e9%a1%8d%e7%9a%84%e8%ae%8a%e5%8c%96-RDrdBlLEby\">\u793a\u4f8b\uff1a\u8a08\u7b97\u92b7\u552e\u984d\u7684\u8b8a\u5316<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>sales<\/code> \u7684\u8868\u683c\uff0c\u7d50\u69cb\u5982\u4e0b\uff1a<\/p>\n<pre>\nCREATE TABLE sales (\n    id INT PRIMARY KEY,\n    sale_date DATE,\n    amount DECIMAL(10, 2)\n);\n<\/pre>\n<p>\u6211\u5011\u60f3\u8981\u6bd4\u8f032022\u5e74\u548c2023\u5e74\u7684\u92b7\u552e\u7e3d\u984d\u3002\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b SQL \u67e5\u8a62\u4f86\u5be6\u73fe\uff1a<\/p>\n<pre>\nSELECT \n    (SELECT SUM(amount) FROM sales WHERE YEAR(sale_date) = 2022) AS total_2022,\n    (SELECT SUM(amount) FROM sales WHERE YEAR(sale_date) = 2023) AS total_2023,\n    ((SELECT SUM(amount) FROM sales WHERE YEAR(sale_date) = 2023) - \n     (SELECT SUM(amount) FROM sales WHERE YEAR(sale_date) = 2022)) AS difference\n<\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6211\u5011\u9996\u5148\u8a08\u7b97\u4e862022\u5e74\u548c2023\u5e74\u7684\u7e3d\u92b7\u552e\u984d\uff0c\u7136\u5f8c\u5c07\u9019\u5169\u500b\u503c\u76f8\u6e1b\uff0c\u5f97\u5230\u4e86\u92b7\u552e\u984d\u7684\u8b8a\u5316\u91cf\u3002<\/p>\n<h2 id=\"%e8%81%9a%e9%9b%86%e5%87%bd%e6%95%b8%e7%9b%b8%e6%b8%9b%e7%9a%84%e6%87%89%e7%94%a8%e5%a0%b4%e6%99%af-RDrdBlLEby\">\u805a\u96c6\u51fd\u6578\u76f8\u6e1b\u7684\u61c9\u7528\u5834\u666f<\/h2>\n<p>\u805a\u96c6\u51fd\u6578\u76f8\u6e1b\u7684\u61c9\u7528\u5834\u666f\u975e\u5e38\u5ee3\u6cdb\uff0c\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5e38\u898b\u7684\u4f8b\u5b50\uff1a<\/p>\n<ul>\n<li><strong>\u8ca1\u52d9\u5831\u544a\uff1a<\/strong>\u4f01\u696d\u53ef\u4ee5\u901a\u904e\u6bd4\u8f03\u4e0d\u540c\u5b63\u5ea6\u6216\u5e74\u5ea6\u7684\u6536\u5165\u4f86\u8a55\u4f30\u696d\u52d9\u8868\u73fe\u3002<\/li>\n<li><strong>\u5e02\u5834\u5206\u6790\uff1a<\/strong>\u901a\u904e\u6bd4\u8f03\u4e0d\u540c\u6642\u9593\u6bb5\u7684\u5e02\u5834\u92b7\u552e\u6578\u64da\uff0c\u4f01\u696d\u53ef\u4ee5\u4e86\u89e3\u5e02\u5834\u8da8\u52e2\u3002<\/li>\n<li><strong>\u6027\u80fd\u76e3\u63a7\uff1a<\/strong>\u5728 IT \u74b0\u5883\u4e2d\uff0c\u901a\u904e\u6bd4\u8f03\u4e0d\u540c\u6642\u9593\u6bb5\u7684\u7cfb\u7d71\u6027\u80fd\u6307\u6a19\uff0c\u53ef\u4ee5\u8b58\u5225\u6f5b\u5728\u7684\u554f\u984c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-RDrdBlLEby\">\u7d50\u8ad6<\/h2>\n<p>\u805a\u96c6\u51fd\u6578\u5728 SQL \u6578\u64da\u5eab\u4e2d\u662f\u975e\u5e38\u91cd\u8981\u7684\u5de5\u5177\uff0c\u901a\u904e\u76f8\u6e1b\u64cd\u4f5c\uff0c\u6211\u5011\u53ef\u4ee5\u7372\u5f97\u6709\u50f9\u503c\u7684\u6578\u64da\u6d1e\u5bdf\u3002\u7121\u8ad6\u662f\u5728\u8ca1\u52d9\u5206\u6790\u3001\u696d\u52d9\u5831\u544a\u9084\u662f\u5e02\u5834\u7814\u7a76\u4e2d\uff0c\u805a\u96c6\u51fd\u6578\u7684\u61c9\u7528\u90fd\u80fd\u5e6b\u52a9\u6211\u5011\u66f4\u597d\u5730\u7406\u89e3\u6578\u64da\u80cc\u5f8c\u7684\u6545\u4e8b\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u5982\u4f55\u5728\u60a8\u7684\u9805\u76ee\u4e2d\u4f7f\u7528 <a href=\"https:\/\/server.hk\">VPS<\/a> \u4f86\u904b\u884c SQL \u6578\u64da\u5eab\u6709\u8208\u8da3\uff0c\u6216\u60f3\u4e86\u89e3\u66f4\u591a\u95dc\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u7684\u8cc7\u8a0a\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8a73\u7d30\u8cc7\u6599\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3SQL\u6578\u64da\u5eab\u4e2d\u805a\u96c6\u51fd\u6578\u7684\u5dee\u7570\uff0c\u5b78\u7fd2\u5982\u4f55\u6709\u6548\u5730\u9032\u884c\u6578\u64da\u805a\u5408\u548c\u76f8\u6e1b\u64cd\u4f5c\uff0c\u63d0\u5347\u6578\u64da\u5206\u6790\u80fd\u529b\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-143915","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143915","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=143915"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143915\/revisions"}],"predecessor-version":[{"id":143916,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143915\/revisions\/143916"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=143915"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=143915"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=143915"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}