{"id":190444,"date":"2024-11-12T12:38:20","date_gmt":"2024-11-12T04:38:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/190444\/"},"modified":"2024-11-12T12:38:21","modified_gmt":"2024-11-12T04:38:21","slug":"%e7%82%ba%e4%bb%80%e9%ba%bcsql%e7%9f%a5%e8%ad%98%e5%b0%8d%e6%95%b8%e6%93%9a%e7%a7%91%e5%ad%b8%e5%ae%b6%e8%87%b3%e9%97%9c%e9%87%8d%e8%a6%81%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/190444\/","title":{"rendered":"\u70ba\u4ec0\u9ebcSQL\u77e5\u8b58\u5c0d\u6578\u64da\u79d1\u5b78\u5bb6\u81f3\u95dc\u91cd\u8981\uff1f"},"content":{"rendered":"<h1 id=\"%e7%82%ba%e4%bb%80%e9%ba%bcsql%e7%9f%a5%e8%ad%98%e5%b0%8d%e6%95%b8%e6%93%9a%e7%a7%91%e5%ad%b8%e5%ae%b6%e8%87%b3%e9%97%9c%e9%87%8d%e8%a6%81%ef%bc%9f-dkmVzQQHdW\">\u70ba\u4ec0\u9ebcSQL\u77e5\u8b58\u5c0d\u6578\u64da\u79d1\u5b78\u5bb6\u81f3\u95dc\u91cd\u8981\uff1f<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0c\u6578\u64da\u79d1\u5b78\u5bb6\u626e\u6f14\u8457\u81f3\u95dc\u91cd\u8981\u7684\u89d2\u8272\u3002\u4ed6\u5011\u7684\u5de5\u4f5c\u4e0d\u50c5\u50c5\u662f\u5206\u6790\u6578\u64da\uff0c\u9084\u5305\u62ec\u5f9e\u5404\u7a2e\u6578\u64da\u6e90\u4e2d\u63d0\u53d6\u3001\u6e05\u7406\u548c\u8f49\u63db\u6578\u64da\u3002SQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u4f5c\u70ba\u4e00\u7a2e\u5f37\u5927\u7684\u6578\u64da\u5eab\u67e5\u8a62\u8a9e\u8a00\uff0c\u5c0d\u6578\u64da\u79d1\u5b78\u5bb6\u7684\u5de5\u4f5c\u81f3\u95dc\u91cd\u8981\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u70ba\u4ec0\u9ebcSQL\u77e5\u8b58\u5c0d\u6578\u64da\u79d1\u5b78\u5bb6\u5982\u6b64\u91cd\u8981\u3002<\/p>\n<h2 id=\"1-%e6%95%b8%e6%93%9a%e5%ad%98%e5%8f%96%e7%9a%84%e5%9f%ba%e7%a4%8e-dkmVzQQHdW\">1. \u6578\u64da\u5b58\u53d6\u7684\u57fa\u790e<\/h2>\n<p>SQL\u662f\u8207\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u9032\u884c\u4ea4\u4e92\u7684\u4e3b\u8981\u8a9e\u8a00\u3002\u6578\u64da\u79d1\u5b78\u5bb6\u7d93\u5e38\u9700\u8981\u5f9e\u6578\u64da\u5eab\u4e2d\u63d0\u53d6\u6578\u64da\uff0c\u4ee5\u4fbf\u9032\u884c\u5206\u6790\u548c\u5efa\u6a21\u3002\u7121\u8ad6\u662f\u4f7f\u7528MySQL\u3001PostgreSQL\u9084\u662f\u5176\u4ed6\u95dc\u4fc2\u578b\u6578\u64da\u5eab\uff0c\u638c\u63e1SQL\u90fd\u80fd\u5e6b\u52a9\u6578\u64da\u79d1\u5b78\u5bb6\u9ad8\u6548\u5730\u5b58\u53d6\u548c\u64cd\u4f5c\u6578\u64da\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b%ef%bc%9a%e5%9f%ba%e6%9c%ac%e7%9a%84sql%e6%9f%a5%e8%a9%a2-dkmVzQQHdW\">\u793a\u4f8b\uff1a\u57fa\u672c\u7684SQL\u67e5\u8a62<\/h3>\n<pre><code>SELECT * FROM customers WHERE country = 'Hong Kong';<\/code><\/pre>\n<p>\u4e0a\u8ff0\u67e5\u8a62\u5c07\u5f9e\u201ccustomers\u201d\u8868\u4e2d\u9078\u64c7\u6240\u6709\u4f86\u81ea\u9999\u6e2f\u7684\u5ba2\u6236\u3002\u9019\u6a23\u7684\u67e5\u8a62\u5c0d\u65bc\u6578\u64da\u79d1\u5b78\u5bb6\u4f86\u8aaa\u662f\u65e5\u5e38\u5de5\u4f5c\u7684\u4e00\u90e8\u5206\u3002<\/p>\n<h2 id=\"2-%e6%95%b8%e6%93%9a%e6%b8%85%e7%90%86%e8%88%87%e8%bd%89%e6%8f%9b-dkmVzQQHdW\">2. \u6578\u64da\u6e05\u7406\u8207\u8f49\u63db<\/h2>\n<p>\u6578\u64da\u6e05\u7406\u662f\u6578\u64da\u79d1\u5b78\u904e\u7a0b\u4e2d\u6700\u91cd\u8981\u7684\u6b65\u9a5f\u4e4b\u4e00\u3002\u6578\u64da\u79d1\u5b78\u5bb6\u9700\u8981\u78ba\u4fdd\u6578\u64da\u7684\u8cea\u91cf\uff0c\u4ee5\u4fbf\u9032\u884c\u6e96\u78ba\u7684\u5206\u6790\u3002SQL\u63d0\u4f9b\u4e86\u591a\u7a2e\u529f\u80fd\u4f86\u6e05\u7406\u548c\u8f49\u63db\u6578\u64da\uff0c\u4f8b\u5982\u4f7f\u7528\u51fd\u6578\u4f86\u8655\u7406\u7f3a\u5931\u503c\u6216\u683c\u5f0f\u4e0d\u6b63\u78ba\u7684\u6578\u64da\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b%ef%bc%9a%e6%95%b8%e6%93%9a%e6%b8%85%e7%90%86-dkmVzQQHdW\">\u793a\u4f8b\uff1a\u6578\u64da\u6e05\u7406<\/h3>\n<pre><code>UPDATE sales SET amount = NULL WHERE amount &lt; 0;<\/code><\/pre>\n<p>\u9019\u689dSQL\u8a9e\u53e5\u5c07\u628a\u201csales\u201d\u8868\u4e2d\u6240\u6709\u8ca0\u6578\u7684\u201camount\u201d\u503c\u8a2d\u7f6e\u70baNULL\uff0c\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u7684\u6e96\u78ba\u6027\u3002<\/p>\n<h2 id=\"3-%e6%95%b8%e6%93%9a%e5%88%86%e6%9e%90%e8%88%87%e5%a0%b1%e5%91%8a-dkmVzQQHdW\">3. \u6578\u64da\u5206\u6790\u8207\u5831\u544a<\/h2>\n<p>\u6578\u64da\u79d1\u5b78\u5bb6\u7d93\u5e38\u9700\u8981\u751f\u6210\u5831\u544a\u548c\u53ef\u8996\u5316\uff0c\u4ee5\u4fbf\u5411\u5229\u76ca\u76f8\u95dc\u8005\u5c55\u793a\u5206\u6790\u7d50\u679c\u3002SQL\u4e0d\u50c5\u53ef\u4ee5\u7528\u4f86\u67e5\u8a62\u6578\u64da\uff0c\u9084\u53ef\u4ee5\u9032\u884c\u805a\u5408\u548c\u5206\u7d44\u64cd\u4f5c\uff0c\u9019\u5c0d\u65bc\u751f\u6210\u5831\u544a\u81f3\u95dc\u91cd\u8981\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b%ef%bc%9a%e6%95%b8%e6%93%9a%e8%81%9a%e5%90%88-dkmVzQQHdW\">\u793a\u4f8b\uff1a\u6578\u64da\u805a\u5408<\/h3>\n<pre><code>SELECT product_id, SUM(sales) as total_sales FROM sales GROUP BY product_id;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8a08\u7b97\u6bcf\u500b\u7522\u54c1\u7684\u7e3d\u92b7\u552e\u984d\uff0c\u4e26\u70ba\u5831\u544a\u63d0\u4f9b\u6709\u50f9\u503c\u7684\u898b\u89e3\u3002<\/p>\n<h2 id=\"4-%e6%95%b8%e6%93%9a%e5%ba%ab%e8%a8%ad%e8%a8%88%e8%88%87%e7%ae%a1%e7%90%86-dkmVzQQHdW\">4. \u6578\u64da\u5eab\u8a2d\u8a08\u8207\u7ba1\u7406<\/h2>\n<p>\u6578\u64da\u79d1\u5b78\u5bb6\u4e0d\u50c5\u9700\u8981\u4f7f\u7528\u6578\u64da\uff0c\u9084\u9700\u8981\u7406\u89e3\u6578\u64da\u5eab\u7684\u7d50\u69cb\u548c\u8a2d\u8a08\u3002\u638c\u63e1SQL\u53ef\u4ee5\u5e6b\u52a9\u6578\u64da\u79d1\u5b78\u5bb6\u66f4\u597d\u5730\u8207\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u5408\u4f5c\uff0c\u8a2d\u8a08\u9ad8\u6548\u7684\u6578\u64da\u5eab\u7d50\u69cb\uff0c\u4ee5\u652f\u6301\u6578\u64da\u5206\u6790\u9700\u6c42\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b%ef%bc%9a%e5%89%b5%e5%bb%ba%e8%a1%a8-dkmVzQQHdW\">\u793a\u4f8b\uff1a\u5275\u5efa\u8868<\/h3>\n<pre><code>CREATE TABLE sales (id INT PRIMARY KEY, product_id INT, amount DECIMAL(10, 2), sale_date DATE);<\/code><\/pre>\n<p>\u9019\u689dSQL\u8a9e\u53e5\u5275\u5efa\u4e86\u4e00\u500b\u201csales\u201d\u8868\uff0c\u6578\u64da\u79d1\u5b78\u5bb6\u53ef\u4ee5\u6839\u64da\u9700\u6c42\u8a2d\u8a08\u6578\u64da\u7d50\u69cb\u3002<\/p>\n<h2 id=\"5-%e6%95%b8%e6%93%9a%e6%95%b4%e5%90%88%e8%88%87etl%e9%81%8e%e7%a8%8b-dkmVzQQHdW\">5. \u6578\u64da\u6574\u5408\u8207ETL\u904e\u7a0b<\/h2>\n<p>\u5728\u8a31\u591a\u60c5\u6cc1\u4e0b\uff0c\u6578\u64da\u79d1\u5b78\u5bb6\u9700\u8981\u5f9e\u591a\u500b\u6578\u64da\u6e90\u6574\u5408\u6578\u64da\u3002SQL\u5728ETL\uff08\u63d0\u53d6\u3001\u8f49\u63db\u3001\u52a0\u8f09\uff09\u904e\u7a0b\u4e2d\u767c\u63ee\u8457\u91cd\u8981\u4f5c\u7528\uff0c\u5e6b\u52a9\u6578\u64da\u79d1\u5b78\u5bb6\u5c07\u4f86\u81ea\u4e0d\u540c\u4f86\u6e90\u7684\u6578\u64da\u6574\u5408\u5230\u4e00\u500b\u7d71\u4e00\u7684\u6578\u64da\u5eab\u4e2d\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b%ef%bc%9a%e6%95%b8%e6%93%9a%e6%95%b4%e5%90%88-dkmVzQQHdW\">\u793a\u4f8b\uff1a\u6578\u64da\u6574\u5408<\/h3>\n<pre><code>INSERT INTO sales (product_id, amount, sale_date) SELECT product_id, amount, sale_date FROM external_sales;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u5f9e\u201cexternal_sales\u201d\u8868\u4e2d\u63d0\u53d6\u6578\u64da\u4e26\u63d2\u5165\u5230\u201csales\u201d\u8868\u4e2d\uff0c\u5be6\u73fe\u6578\u64da\u7684\u6574\u5408\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-dkmVzQQHdW\">\u7e3d\u7d50<\/h2>\n<p>\u7e3d\u7684\u4f86\u8aaa\uff0cSQL\u77e5\u8b58\u5c0d\u6578\u64da\u79d1\u5b78\u5bb6\u81f3\u95dc\u91cd\u8981\uff0c\u56e0\u70ba\u5b83\u4e0d\u50c5\u5e6b\u52a9\u4ed6\u5011\u6709\u6548\u5730\u5b58\u53d6\u548c\u64cd\u4f5c\u6578\u64da\uff0c\u9084\u652f\u6301\u6578\u64da\u6e05\u7406\u3001\u5206\u6790\u3001\u5831\u544a\u548c\u6574\u5408\u7b49\u591a\u500b\u65b9\u9762\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\u548c\u8907\u96dc\u6027\u7684\u63d0\u9ad8\uff0c\u638c\u63e1SQL\u5c07\u4f7f\u6578\u64da\u79d1\u5b78\u5bb6\u5728\u8077\u696d\u751f\u6daf\u4e2d\u66f4\u5177\u7af6\u722d\u529b\u3002\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5b58\u5132\u89e3\u6c7a\u65b9\u6848\uff0c\u53ef\u4ee5\u8003\u616e\u6211\u5011\u7684<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u670d\u52d9\uff0c\u70ba\u60a8\u7684\u6578\u64da\u79d1\u5b78\u9805\u76ee\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3SQL\u5c0d\u6578\u64da\u79d1\u5b78\u5bb6\u7684\u91cd\u8981\u6027\uff0c\u56e0\u70ba\u5b83\u662f\u6578\u64da\u67e5\u8a62\u3001\u7ba1\u7406\u548c\u5206\u6790\u7684\u57fa\u790e\u5de5\u5177\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\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-190444","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/190444","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=190444"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/190444\/revisions"}],"predecessor-version":[{"id":190445,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/190444\/revisions\/190445"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=190444"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=190444"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=190444"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}