{"id":714,"date":"2017-09-18T15:12:29","date_gmt":"2017-09-18T07:12:29","guid":{"rendered":"http:\/\/www.mrtblog.cn\/?p=714"},"modified":"2017-09-18T15:15:13","modified_gmt":"2017-09-18T07:15:13","slug":"csqlite3%e5%a4%9a%e5%88%97%e6%93%8d%e4%bd%9c","status":"publish","type":"post","link":"http:\/\/www.mrtblog.cn\/?p=714","title":{"rendered":"[C#]Sqlite3\u591a\u884c\u591a\u5217\u64cd\u4f5c"},"content":{"rendered":"<div class='epvc-post-count'><span class='epvc-eye'><\/span>  <span class=\"epvc-count\"> 1,453<\/span><span class='epvc-label'> Views<\/span><\/div><p>1.\u591a\u5217\u6570\u636e\u7ec4\u5408\uff08\u4e3b\u8981\u662f\u5b57\u7b26\u4e32\u62fc\u63a5\uff09<br \/>\nA:<br \/>\nC1&nbsp;&nbsp;&nbsp;&nbsp;C2<br \/>\n1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a<br \/>\n2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b<br \/>\n3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c<br \/>\n\u5bf9C1\u548cC2\u505a&#8221;=&#8221;\u62fc\u63a5\u7ed3\u679c\u4e3a\uff1a<br \/>\nA:<br \/>\nC12<br \/>\n1=a<br \/>\n2=b<br \/>\n3=c<\/p>\n<pre>select C1||\"=\"||C2 as C12 from A;<\/pre>\n<p>2.\u591a\u8868\u591a\u5217\u5408\u5e76<br \/>\nA:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;B:<br \/>\nC1&nbsp;&nbsp;&nbsp;&nbsp;C2&nbsp;&nbsp;&nbsp;&nbsp;C1&nbsp;&nbsp;&nbsp;&nbsp;C3<br \/>\n1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1<br \/>\n2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2<br \/>\n3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1<br \/>\n\u8981\u6309\u7167C1\u7d22\u5f15\u5408\u5e76\uff0c\u4e14\u5c06B\u8868\u4e2dC1\u91cd\u590d\u7684\u884c\u5408\u5e76\uff0c\u7ed3\u679c\u4e3a:<br \/>\nnew A:<br \/>\nC1&nbsp;&nbsp;&nbsp;&nbsp;C2&nbsp;&nbsp;&nbsp;&nbsp;C3<br \/>\n1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1,2<br \/>\n2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1<br \/>\n3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;null<\/p>\n<pre>select A.C1,A.C2,GROUP_CONCAT(B.C3) as C3 from A join B GROUP BY A.C1<\/pre>\n<p>3.\u591a\u884c\u6570\u636e\u64cd\u4f5c<br \/>\nA:<br \/>\nC1<br \/>\n1.0<br \/>\n2.1<br \/>\n3.3<br \/>\n\u5bf9C1\u6c42\u548c\uff0c\u4e14\u4fdd\u7559\u7cbe\u5ea6\uff0c\u7ed3\u679c\u4e3a\uff1a<br \/>\nA:<br \/>\nsum(C1)<br \/>\n6.4<\/p>\n<pre>select round(sum(C1),6) from A<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>1,453 Views1.\u591a\u5217\u6570\u636e\u7ec4\u5408\uff08\u4e3b\u8981\u662f\u5b57\u7b26\u4e32\u62fc\u63a5\uff09 A: C1&nbsp;&nbsp;&nbsp;&#038;n [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[92],"tags":[],"class_list":["post-714","post","type-post","status-publish","format-standard","hentry","category-project"],"_links":{"self":[{"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/714","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=714"}],"version-history":[{"count":16,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/714\/revisions"}],"predecessor-version":[{"id":1232,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/714\/revisions\/1232"}],"wp:attachment":[{"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=714"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=714"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.mrtblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=714"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}