{"id":1792,"date":"2015-09-13T08:58:17","date_gmt":"2015-09-13T00:58:17","guid":{"rendered":"http:\/\/www.821121.com\/?p=1792"},"modified":"2022-10-13T09:27:53","modified_gmt":"2022-10-13T01:27:53","slug":"%e5%ad%a6%e4%b9%a0%e7%ac%94%e8%ae%b0sql-group-by%e5%88%86%e7%bb%84","status":"publish","type":"post","link":"http:\/\/www.821121.com\/?p=1792","title":{"rendered":"\u5b66\u4e60\u7b14\u8bb0SQL-Group By\u5206\u7ec4"},"content":{"rendered":"<p>GroupBy\u8bed\u53e5\u4ece\u82f1\u6587\u7684\u5b57\u9762\u610f\u4e49\u4e0a\u7406\u89e3\u5c31\u662f\u201c\u6839\u636e(by)\u4e00\u5b9a\u7684\u89c4\u5219\u8fdb\u884c\u5206\u7ec4(Group)\u201d\u3002\u5b83\u7684\u4f5c\u7528\u662f\u901a\u8fc7\u4e00\u5b9a\u7684\u89c4\u5219\u5c06\u4e00\u4e2a\u6570\u636e\u96c6\u5212\u5206\u6210\u82e5\u5e72\u4e2a\u5c0f\u7684\u533a\u57df\uff0c\u7136\u540e\u9488\u5bf9\u82e5\u5e72\u4e2a\u5c0f\u533a\u57df\u8fdb\u884c\u6570\u636e\u5904\u7406\u3002<\/p>\n<p>GROUP\u8868\u793a\u5206\u7ec4\uff0cBY\u540e\u9762\u5199\u5b57\u6bb5\u540d\uff0c\u5c31\u8868\u793a\u6839\u636e\u54ea\u4e2a\u5b57\u6bb5\u8fdb\u884c\u5206\u7ec4\uff0cGROUP BY\u5fc5\u987b\u5f97\u914d\u5408\u805a\u5408\u51fd\u6570\u6765\u7528\uff0c\u5206\u7ec4\u4e4b\u540e\u4f60\u53ef\u4ee5\u8ba1\u6570\uff08COUNT\uff09\uff0c\u6c42\u548c\uff08SUM\uff09\uff0c\u6c42\u5e73\u5747\u6570\uff08AVG\uff09\u7b49\u3002<\/p>\n<pre><code class=\"language-shell\">select deptno,avg(sal) from emp group by deptno;<\/code><\/pre>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/10\/1665623969535.png\" alt=\"\" \/><br \/>\n\u51fa\u73b0\u5728select\u540e\u9762\u7684\u5b57\u6bb5\uff0c\u8981\u4e48\u7528\u5728\u5206\u7ec4\u4e2d\uff0c\u8981\u4e48\u7528\u5728\u805a\u5408\u51fd\u6570\u4e2d\uff0c\u5982\u679c\u6709\u591a\u4f59\u7684\u4f1a\u62a5\u9519\u3002<\/p>\n<pre><code class=\"language-shell\">select deptno,job,avg(sal) from emp group by deptno;<\/code><\/pre>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/10\/image-1665624338977.png\" alt=\"file\" \/><\/p>\n<pre><code class=\"language-shell\">select deptno,job,avg(sal) from emp group by deptno,job;<\/code><\/pre>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/10\/image-1665624359183.png\" alt=\"file\" \/><br \/>\n\u8fd9\u91cc\u76f8\u540cdeptno\uff0c\u4e0d\u540cjob\u89c6\u4e3a\u4e00\u4e2a\u65b0\u7ec4\u3002<br \/>\n\u4f7f\u7528having\u51fd\u6570\u5bf9\u5206\u7ec4\u540e\u7684\u6570\u636e\u8fdb\u884c\u8fc7\u6ee4\uff1a<\/p>\n<pre><code class=\"language-shell\">select ename,job,avg(sal) from emp group by ename,job having avg(sal)&gt;=2000;<\/code><\/pre>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/10\/image-1665624384974.png\" alt=\"file\" \/><br \/>\n\u6ce8\u610f\uff1a<br \/>\nwhere\u8981\u653e\u5728group by\u524d\u9762<br \/>\ngroup by \u540e\u9762\u52a0\u6761\u4ef6\u53ea\u80fd\u7528having\u5173\u952e\u5b57<\/p>\n<p>\u4f7f\u7528\u805a\u5408\u51fd\u6570\u65f6\uff0c\u4f1a\u81ea\u52a8\u5ffd\u7565\u7a7a\u503c\u3002<\/p>\n<pre><code class=\"language-shell\">select sum(comm),count(*),avg(comm) &quot;Average number of people with bonus&quot; from emp;<\/code><\/pre>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/10\/image-1665624408163.png\" alt=\"file\" \/><br \/>\n\u90a3\u4e48\u5982\u4f55\u4e0d\u5ffd\u7565\u5462\uff0c\u9700\u8981\u7528\u5230nvl\u51fd\u6570\uff0cnvl(x,y)x\u82e5\u4e3a\u7a7a\uff0c\u5219\u503c\u4e3ay\uff0cx\u82e5\u4e0d\u7a7a\uff0c\u5219\u503c\u4e3ax\u3002<\/p>\n<pre><code>select sum(comm),count(*),avg(nvl(comm,0)) &quot;Average number of all people&quot; from emp;<\/code><\/pre>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/10\/image-1665624437560.png\" alt=\"file\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>GroupBy\u8bed\u53e5\u4ece\u82f1\u6587\u7684\u5b57\u9762\u610f\u4e49\u4e0a\u7406\u89e3\u5c31\u662f\u201c\u6839\u636e<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1792","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/posts\/1792","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.821121.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1792"}],"version-history":[{"count":1,"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/posts\/1792\/revisions"}],"predecessor-version":[{"id":1802,"href":"http:\/\/www.821121.com\/index.php?rest_route=\/wp\/v2\/posts\/1792\/revisions\/1802"}],"wp:attachment":[{"href":"http:\/\/www.821121.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1792"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.821121.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1792"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.821121.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1792"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}