{"id":59605,"date":"2024-10-12T23:21:13","date_gmt":"2024-10-12T15:21:13","guid":{"rendered":"https:\/\/server.hk\/cnblog\/59605\/"},"modified":"2024-10-12T23:21:13","modified_gmt":"2024-10-12T15:21:13","slug":"cmu-15445-%e5%ad%b8%e7%bf%92%e4%b9%8badvanced-sql","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/59605\/","title":{"rendered":"CMU 15445 \u5b78\u7fd2\u4e4bAdvanced SQL"},"content":{"rendered":"<h1 id=\"cmu-15445-%e5%ad%b8%e7%bf%92%e4%b9%8badvanced-sql-sPQeNMXHIm\">CMU 15445 \u5b78\u7fd2\u4e4bAdvanced SQL<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u5df2\u6210\u70ba\u6578\u64da\u5eab\u7ba1\u7406\u548c\u6578\u64da\u5206\u6790\u7684\u6838\u5fc3\u5de5\u5177\u4e4b\u4e00\u3002\u5361\u5167\u57fa\u6885\u9686\u5927\u5b78\u7684CMU 15445\u8ab2\u7a0b\u5c08\u6ce8\u65bc\u9ad8\u7d1aSQL\u7684\u61c9\u7528\uff0c\u65e8\u5728\u5e6b\u52a9\u5b78\u751f\u6df1\u5165\u7406\u89e3SQL\u7684\u8907\u96dc\u6027\u53ca\u5176\u5728\u5be6\u969b\u61c9\u7528\u4e2d\u7684\u6f5b\u529b\u3002<\/p>\n<h2 id=\"%e8%aa%b2%e7%a8%8b%e6%a6%82%e8%bf%b0-sPQeNMXHIm\">\u8ab2\u7a0b\u6982\u8ff0<\/h2>\n<p>CMU 15445\u8ab2\u7a0b\u4e3b\u8981\u6db5\u84cb\u4ee5\u4e0b\u5e7e\u500b\u65b9\u9762\uff1a<\/p>\n<ul>\n<li>SQL\u7684\u9ad8\u7d1a\u7279\u6027<\/li>\n<li>\u6578\u64da\u5eab\u8a2d\u8a08\u8207\u5efa\u6a21<\/li>\n<li id=\"%e6%9f%a5%e8%a9%a2%e5%84%aa%e5%8c%96%e6%8a%80%e8%a1%93-sPQeNMXHIm\">\u67e5\u8a62\u512a\u5316\u6280\u8853<\/li>\n<li id=\"%e4%ba%8b%e5%8b%99%e8%99%95%e7%90%86%e8%88%87%e4%b8%a6%e7%99%bc%e6%8e%a7%e5%88%b6-sPQeNMXHIm\">\u4e8b\u52d9\u8655\u7406\u8207\u4e26\u767c\u63a7\u5236<\/li>\n<li id=\"%e6%95%b8%e6%93%9a%e5%ba%ab%e5%ae%89%e5%85%a8%e6%80%a7-sPQeNMXHIm\">\u6578\u64da\u5eab\u5b89\u5168\u6027<\/li>\n<\/ul>\n<h2 id=\"%e9%ab%98%e7%b4%9asql%e7%89%b9%e6%80%a7-sPQeNMXHIm\">\u9ad8\u7d1aSQL\u7279\u6027<\/h2>\n<p>\u9ad8\u7d1aSQL\u4e0d\u50c5\u50c5\u662f\u57fa\u672c\u7684\u67e5\u8a62\u8a9e\u53e5\uff0c\u5b83\u9084\u5305\u62ec\u4e86\u8a31\u591a\u8907\u96dc\u7684\u529f\u80fd\uff0c\u4f8b\u5982\u7a97\u53e3\u51fd\u6578\u3001CTE\uff08\u516c\u7528\u8868\u9054\u5f0f\uff09\u548c\u5b50\u67e5\u8a62\u7b49\u3002\u9019\u4e9b\u529f\u80fd\u4f7f\u5f97\u7528\u6236\u80fd\u5920\u66f4\u9748\u6d3b\u5730\u8655\u7406\u6578\u64da\u3002<\/p>\n<h3 id=\"%e7%aa%97%e5%8f%a3%e5%87%bd%e6%95%b8-sPQeNMXHIm\">\u7a97\u53e3\u51fd\u6578<\/h3>\n<p>\u7a97\u53e3\u51fd\u6578\u5141\u8a31\u7528\u6236\u5728\u67e5\u8a62\u7d50\u679c\u4e2d\u9032\u884c\u8a08\u7b97\uff0c\u800c\u4e0d\u9700\u8981\u5c07\u6578\u64da\u5206\u7d44\u3002\u9019\u5c0d\u65bc\u9700\u8981\u9032\u884c\u7d2f\u8a08\u3001\u6392\u540d\u6216\u79fb\u52d5\u5e73\u5747\u7b49\u64cd\u4f5c\u7684\u60c5\u6cc1\u7279\u5225\u6709\u7528\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528\u7a97\u53e3\u51fd\u6578\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>SELECT \n    employee_id, \n    salary, \n    RANK() OVER (ORDER BY salary DESC) AS salary_rank \nFROM \n    employees;<\/code><\/pre>\n<h3 id=\"%e5%85%ac%e7%94%a8%e8%a1%a8%e9%81%94%e5%bc%8f%ef%bc%88cte%ef%bc%89-sPQeNMXHIm\">\u516c\u7528\u8868\u9054\u5f0f\uff08CTE\uff09<\/h3>\n<p>CTE\u4f7f\u5f97\u67e5\u8a62\u66f4\u5177\u53ef\u8b80\u6027\uff0c\u4e26\u4e14\u53ef\u4ee5\u5728\u540c\u4e00\u67e5\u8a62\u4e2d\u91cd\u8907\u4f7f\u7528\u3002\u4ee5\u4e0b\u662f\u4e00\u500bCTE\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>WITH DepartmentSalaries AS (\n    SELECT \n        department_id, \n        AVG(salary) AS avg_salary \n    FROM \n        employees \n    GROUP BY \n        department_id\n)\nSELECT \n    d.department_name, \n    ds.avg_salary \nFROM \n    departments d \nJOIN \n    DepartmentSalaries ds ON d.department_id = ds.department_id;<\/code><\/pre>\n<h2 id=\"%e6%9f%a5%e8%a9%a2%e5%84%aa%e5%8c%96%e6%8a%80%e8%a1%93-sPQeNMXHIm\">\u67e5\u8a62\u512a\u5316\u6280\u8853<\/h2>\n<p>\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\uff0c\u67e5\u8a62\u7684\u6027\u80fd\u81f3\u95dc\u91cd\u8981\u3002CMU 15445\u8ab2\u7a0b\u4e2d\uff0c\u5b78\u751f\u5c07\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528\u57f7\u884c\u8a08\u5283\u4f86\u5206\u6790\u67e5\u8a62\u6027\u80fd\uff0c\u4e26\u901a\u904e\u7d22\u5f15\u3001\u5206\u5340\u548c\u5176\u4ed6\u6280\u8853\u4f86\u512a\u5316\u67e5\u8a62\u3002<\/p>\n<h3 id=\"%e5%9f%b7%e8%a1%8c%e8%a8%88%e5%8a%83-sPQeNMXHIm\">\u57f7\u884c\u8a08\u5283<\/h3>\n<p>\u57f7\u884c\u8a08\u5283\u662f\u6578\u64da\u5eab\u7cfb\u7d71\u7528\u4f86\u57f7\u884c\u67e5\u8a62\u7684\u6b65\u9a5f\u3002\u901a\u904e\u5206\u6790\u57f7\u884c\u8a08\u5283\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u8b58\u5225\u6027\u80fd\u74f6\u9838\u4e26\u9032\u884c\u76f8\u61c9\u7684\u512a\u5316\u3002\u4ee5\u4e0b\u662f\u5982\u4f55\u67e5\u770b\u57f7\u884c\u8a08\u5283\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>EXPLAIN SELECT * FROM employees WHERE department_id = 10;<\/code><\/pre>\n<h2 id=\"%e4%ba%8b%e5%8b%99%e8%99%95%e7%90%86%e8%88%87%e4%b8%a6%e7%99%bc%e6%8e%a7%e5%88%b6-sPQeNMXHIm\">\u4e8b\u52d9\u8655\u7406\u8207\u4e26\u767c\u63a7\u5236<\/h2>\n<p>\u4e8b\u52d9\u8655\u7406\u662f\u78ba\u4fdd\u6578\u64da\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\u7684\u95dc\u9375\u3002\u5b78\u751f\u5c07\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528ACID\uff08\u539f\u5b50\u6027\u3001\u4e00\u81f4\u6027\u3001\u9694\u96e2\u6027\u3001\u6301\u4e45\u6027\uff09\u539f\u5247\u4f86\u8a2d\u8a08\u53ef\u9760\u7684\u6578\u64da\u5eab\u7cfb\u7d71\u3002\u6b64\u5916\uff0c\u4e26\u767c\u63a7\u5236\u6280\u8853\u5982\u9396\u548c\u591a\u7248\u672c\u4e26\u767c\u63a7\u5236\uff08MVCC\uff09\u4e5f\u5c07\u88ab\u6df1\u5165\u63a2\u8a0e\u3002<\/p>\n<h2 id=\"%e6%95%b8%e6%93%9a%e5%ba%ab%e5%ae%89%e5%85%a8%e6%80%a7-sPQeNMXHIm\">\u6578\u64da\u5eab\u5b89\u5168\u6027<\/h2>\n<p>\u96a8\u8457\u6578\u64da\u6cc4\u9732\u4e8b\u4ef6\u7684\u983b\u7e41\u767c\u751f\uff0c\u6578\u64da\u5eab\u5b89\u5168\u6027\u8b8a\u5f97\u8d8a\u4f86\u8d8a\u91cd\u8981\u3002\u8ab2\u7a0b\u5c07\u6db5\u84cb\u7528\u6236\u6b0a\u9650\u7ba1\u7406\u3001\u6578\u64da\u52a0\u5bc6\u548c\u5b89\u5168\u5be9\u8a08\u7b49\u4e3b\u984c\uff0c\u4ee5\u5e6b\u52a9\u5b78\u751f\u7406\u89e3\u5982\u4f55\u4fdd\u8b77\u6578\u64da\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-sPQeNMXHIm\">\u7e3d\u7d50<\/h2>\n<p>CMU 15445\u7684\u9ad8\u7d1aSQL\u8ab2\u7a0b\u70ba\u5b78\u751f\u63d0\u4f9b\u4e86\u6df1\u5165\u7684\u6578\u64da\u5eab\u77e5\u8b58\u548c\u5be6\u8e10\u7d93\u9a57\uff0c\u5e6b\u52a9\u4ed6\u5011\u5728\u6578\u64da\u9a45\u52d5\u7684\u74b0\u5883\u4e2d\u812b\u7a4e\u800c\u51fa\u3002\u7121\u8ad6\u662f\u67e5\u8a62\u512a\u5316\u3001\u4e8b\u52d9\u8655\u7406\u9084\u662f\u6578\u64da\u5eab\u5b89\u5168\u6027\uff0c\u9019\u4e9b\u6280\u80fd\u90fd\u5c07\u5728\u672a\u4f86\u7684\u8077\u696d\u751f\u6daf\u4e2d\u767c\u63ee\u91cd\u8981\u4f5c\u7528\u3002\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7ba1\u7406\u548c\u9ad8\u7d1aSQL\u6709\u8208\u8da3\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u4f86\u642d\u5efa\u60a8\u7684\u5be6\u9a57\u74b0\u5883\uff0c\u9032\u4e00\u6b65\u63d0\u5347\u60a8\u7684\u6280\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Master advanced SQL concepts with CMU 15445, enhancing your data manipulation skills for complex queries and database management.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-59605","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/59605","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=59605"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/59605\/revisions"}],"predecessor-version":[{"id":59606,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/59605\/revisions\/59606"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=59605"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=59605"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=59605"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}