{"id":168507,"date":"2024-11-06T12:57:23","date_gmt":"2024-11-06T04:57:23","guid":{"rendered":"https:\/\/server.hk\/cnblog\/168507\/"},"modified":"2024-11-06T12:57:23","modified_gmt":"2024-11-06T04:57:23","slug":"sql-%e4%b8%ad-stdev-%e5%87%bd%e6%95%b8%e8%88%87-stdevp-%e5%87%bd%e6%95%b8%e7%9a%84%e5%8d%80%e5%88%a5","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/168507\/","title":{"rendered":"SQL \u4e2d StDev \u51fd\u6578\u8207 StDevP \u51fd\u6578\u7684\u5340\u5225"},"content":{"rendered":"<h1 id=\"sql-%e4%b8%ad-stdev-%e5%87%bd%e6%95%b8%e8%88%87-stdevp-%e5%87%bd%e6%95%b8%e7%9a%84%e5%8d%80%e5%88%a5-nKWRSRbzca\">SQL \u4e2d StDev \u51fd\u6578\u8207 StDevP \u51fd\u6578\u7684\u5340\u5225<\/h1>\n<p>\u5728 SQL \u4e2d\uff0c\u7d71\u8a08\u51fd\u6578\u662f\u6578\u64da\u5206\u6790\u7684\u91cd\u8981\u5de5\u5177\uff0c\u5176\u4e2d <code>StDev<\/code> \u548c <code>StDevP<\/code> \u51fd\u6578\u5e38\u88ab\u7528\u4f86\u8a08\u7b97\u6578\u64da\u96c6\u7684\u6a19\u6e96\u5dee\u3002\u96d6\u7136\u9019\u5169\u500b\u51fd\u6578\u7684\u540d\u7a31\u76f8\u4f3c\uff0c\u4f46\u5b83\u5011\u7684\u8a08\u7b97\u65b9\u5f0f\u548c\u9069\u7528\u60c5\u5883\u537b\u6709\u6240\u4e0d\u540c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u9019\u5169\u500b\u51fd\u6578\u7684\u5340\u5225\u53ca\u5176\u4f7f\u7528\u60c5\u5883\u3002<\/p>\n<h2 id=\"%e6%a8%99%e6%ba%96%e5%b7%ae%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-nKWRSRbzca\">\u6a19\u6e96\u5dee\u7684\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>\u6a19\u6e96\u5dee\u662f\u4e00\u7a2e\u8861\u91cf\u6578\u64da\u5206\u6563\u7a0b\u5ea6\u7684\u6307\u6a19\u3002\u5b83\u53cd\u6620\u4e86\u6578\u64da\u9ede\u8207\u5176\u5e73\u5747\u503c\u4e4b\u9593\u7684\u5dee\u7570\u3002\u6a19\u6e96\u5dee\u8d8a\u5927\uff0c\u8868\u793a\u6578\u64da\u7684\u8b8a\u7570\u6027\u8d8a\u9ad8\uff1b\u53cd\u4e4b\uff0c\u6a19\u6e96\u5dee\u8d8a\u5c0f\uff0c\u5247\u6578\u64da\u8f03\u70ba\u96c6\u4e2d\u3002<\/p>\n<h2 id=\"stdev-%e5%87%bd%e6%95%b8-nKWRSRbzca\">StDev \u51fd\u6578<\/h2>\n<p><code>StDev<\/code> \u51fd\u6578\u7528\u65bc\u8a08\u7b97\u6a23\u672c\u6a19\u6e96\u5dee\u3002\u9019\u610f\u5473\u8457\u5b83\u662f\u57fa\u65bc\u6578\u64da\u96c6\u7684\u4e00\u90e8\u5206\uff08\u5373\u6a23\u672c\uff09\u4f86\u4f30\u7b97\u6574\u9ad4\u7684\u6a19\u6e96\u5dee\u3002\u5176\u8a08\u7b97\u516c\u5f0f\u70ba\uff1a<\/p>\n<pre><code>StDev = SQRT(SUM((x - AVG(x))^2) \/ (n - 1))<\/code><\/pre>\n<p>\u5176\u4e2d\uff0c<code>x<\/code> \u662f\u6578\u64da\u9ede\uff0c<code>AVG(x)<\/code> \u662f\u6578\u64da\u7684\u5e73\u5747\u503c\uff0c<code>n<\/code> \u662f\u6a23\u672c\u7684\u6578\u91cf\u3002\u7531\u65bc <code>StDev<\/code> \u662f\u57fa\u65bc\u6a23\u672c\u8a08\u7b97\u7684\uff0c\u56e0\u6b64\u5728\u8a08\u7b97\u6642\u6703\u4f7f\u7528 <code>n - 1<\/code> \u4f5c\u70ba\u5206\u6bcd\uff0c\u9019\u88ab\u7a31\u70ba\u300c\u81ea\u7531\u5ea6\u4fee\u6b63\u300d\uff0c\u4ee5\u63d0\u9ad8\u4f30\u7b97\u7684\u6e96\u78ba\u6027\u3002<\/p>\n<h3 id=\"%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-nKWRSRbzca\">\u4f7f\u7528\u7bc4\u4f8b<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>Sales<\/code> \u7684\u8868\u683c\uff0c\u5305\u542b\u4ee5\u4e0b\u92b7\u552e\u6578\u64da\uff1a<\/p>\n<pre><code>SELECT StDev(SalesAmount) AS SampleStdDev\nFROM Sales;<\/code><\/pre>\n<p>\u9019\u6bb5 SQL \u8a9e\u53e5\u5c07\u8a08\u7b97 <code>SalesAmount<\/code> \u7684\u6a23\u672c\u6a19\u6e96\u5dee\u3002<\/p>\n<h2 id=\"stdevp-%e5%87%bd%e6%95%b8-nKWRSRbzca\">StDevP \u51fd\u6578<\/h2>\n<p>\u76f8\u5c0d\u65bc <code>StDev<\/code>\uff0c<code>StDevP<\/code> \u51fd\u6578\u7528\u65bc\u8a08\u7b97\u6574\u9ad4\u6a19\u6e96\u5dee\u3002\u9019\u610f\u5473\u8457\u5b83\u5047\u8a2d\u6240\u63d0\u4f9b\u7684\u6578\u64da\u96c6\u662f\u6574\u9ad4\u6578\u64da\u7684\u5b8c\u6574\u8868\u793a\uff0c\u800c\u4e0d\u662f\u6a23\u672c\u3002\u5176\u8a08\u7b97\u516c\u5f0f\u70ba\uff1a<\/p>\n<pre><code>StDevP = SQRT(SUM((x - AVG(x))^2) \/ n)<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>n<\/code> \u662f\u6578\u64da\u96c6\u4e2d\u7684\u6240\u6709\u6578\u64da\u9ede\u7684\u6578\u91cf\u3002\u7531\u65bc <code>StDevP<\/code> \u662f\u57fa\u65bc\u6574\u9ad4\u8a08\u7b97\u7684\uff0c\u56e0\u6b64\u4e0d\u9700\u8981\u9032\u884c\u81ea\u7531\u5ea6\u4fee\u6b63\u3002<\/p>\n<h3 id=\"%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-nKWRSRbzca\">\u4f7f\u7528\u7bc4\u4f8b<\/h3>\n<p>\u540c\u6a23\u5730\uff0c\u5c0d\u65bc <code>Sales<\/code> \u8868\u683c\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b SQL \u8a9e\u53e5\u4f86\u8a08\u7b97\u6574\u9ad4\u6a19\u6e96\u5dee\uff1a<\/p>\n<pre><code>SELECT StDevP(SalesAmount) AS PopulationStdDev\nFROM Sales;<\/code><\/pre>\n<p>\u9019\u6bb5 SQL \u8a9e\u53e5\u5c07\u8a08\u7b97 <code>SalesAmount<\/code> \u7684\u6574\u9ad4\u6a19\u6e96\u5dee\u3002<\/p>\n<h2 id=\"stdev-%e8%88%87-stdevp-%e7%9a%84%e9%81%b8%e6%93%87-nKWRSRbzca\">StDev \u8207 StDevP \u7684\u9078\u64c7<\/h2>\n<p>\u5728\u9078\u64c7\u4f7f\u7528 <code>StDev<\/code> \u9084\u662f <code>StDevP<\/code> \u6642\uff0c\u4e3b\u8981\u53d6\u6c7a\u65bc\u6578\u64da\u7684\u6027\u8cea\u3002\u5982\u679c\u4f60\u64c1\u6709\u6574\u9ad4\u6578\u64da\uff0c\u5247\u61c9\u4f7f\u7528 <code>StDevP<\/code>\uff1b\u5982\u679c\u4f60\u53ea\u64c1\u6709\u6578\u64da\u7684\u4e00\u90e8\u5206\uff08\u6a23\u672c\uff09\uff0c\u5247\u61c9\u4f7f\u7528 <code>StDev<\/code>\u3002\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u8a08\u7b97\u7d50\u679c\u7684\u6e96\u78ba\u6027\u548c\u53ef\u9760\u6027\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-nKWRSRbzca\">\u7e3d\u7d50<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c<code>StDev<\/code> \u548c <code>StDevP<\/code> \u51fd\u6578\u5404\u6709\u5176\u7279\u5b9a\u7684\u7528\u9014\u548c\u8a08\u7b97\u65b9\u5f0f\u3002\u4e86\u89e3\u9019\u5169\u8005\u4e4b\u9593\u7684\u5340\u5225\u5c0d\u65bc\u6578\u64da\u5206\u6790\u81f3\u95dc\u91cd\u8981\u3002\u9078\u64c7\u6b63\u78ba\u7684\u51fd\u6578\u53ef\u4ee5\u5e6b\u52a9\u4f60\u66f4\u6e96\u78ba\u5730\u7406\u89e3\u6578\u64da\u7684\u8b8a\u7570\u6027\uff0c\u5f9e\u800c\u505a\u51fa\u66f4\u660e\u667a\u7684\u6c7a\u7b56\u3002<\/p>\n<p>\u5982\u679c\u4f60\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u9700\u6c42\u7684\u5ba2\u6236\u3002\u7121\u8ad6\u662f <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u9084\u662f\u5176\u4ed6\u96f2\u670d\u52d9\uff0c\u6211\u5011\u90fd\u80fd\u70ba\u4f60\u63d0\u4f9b\u7a69\u5b9a\u53ef\u9760\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3 SQL \u4e2d StDev \u51fd\u6578\u8207 StDevP \u51fd\u6578\u7684\u4e3b\u8981\u5340\u5225\uff0c\u524d\u8005\u8a08\u7b97\u6a23\u672c\u6a19\u6e96\u5dee\uff0c\u5f8c\u8005\u8a08\u7b97\u6574\u9ad4\u6a19\u6e96\u5dee\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-168507","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168507","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=168507"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168507\/revisions"}],"predecessor-version":[{"id":168508,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168507\/revisions\/168508"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=168507"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=168507"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=168507"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}