在SQL中,可以使用CASE WHEN和IN语句来创建计算列。计算列是一种虚拟列,它不在表中存储实际的数据,而是根据其他列的值进行计算得出的结果。 CASE WHEN语句用于根据条件进行条件判断和计算。它的语法如下: 代码语言:txt 复制 CASE WHEN condition1 THEN result1 WHEN condition2 THEN result2 ... ELSE result END...
when FPGCDM = '00014' then '宜宾校区' else '本部校区' end as XQ from bigdata_book_information WHERE RCRQ <= CONCAT(YEAR(NOW()) - 1, "0831") and skztm not in ('34','35','36','37','38','3B','3c') GROUP BY XQ
isnull(sum(case course when '高级班' then score end),0) as '高级班', isnull(sum(case course when '架构班' then score end),0) as '架构班', isnull(sum(case course when '上位机班' then score end),0) as '上位机班', isnull(sum(case course when 'Web前端' then score end),0)...
1.casewhen用在取字段名上selectid,username (casewhenf.answererisnotnullthen1else0end)asisAnswer ffromuser2.根据区间进行选择值selectcasewhentypein(1,2)then1whentypein(3,4)then2whentypein(5,6,7,8)then3whentypein(9,10,11,12,13,14,15)then4whentypein(16,17,18)then5whentypein(19,20,...
SQL CASE WHEN语句性能优化,背景:性能应该是功能的一个重要参考,特别是在大数据的背景之下!写SQL语句时如果仅考虑业务逻辑,而不去考虑语句效率问题,有可能导致严重的效率问题,导致功能不可用或者资源消耗过大。其中的一种情况是,处理每日增量数据的程序,实际执行过
CASE WHEN是SQL中特有的查询关键字,这个组合在PowerBI中是没有的。 白茶在之前介绍PowerBI中IF的时候曾经说过,SWITCH底层逻辑和IF是一样的,只不过是写法上更加的优雅。但是在SQL中比SWITCH更好用的,是CASE WHEN。 语法 CASE WHEN语法一共有两种。 语法1: ...
记录日常使用中sql语句中,多个函数使用 SELECTa.co1,CASEWHENLEFT(hangye,2)in(13,14,15,16)THEN'食品'WHENLEFT(hangye,2)in(17,18,19,28)THEN'纺织'ELSE'其他'ENDASLeixing,a.zhandi,shuishou,xiaoshouFROMtable1 aWHERE1=1 一般的case when 使用的方法是在 case 后添加 字段 然后在用 when 去判断...
I am working with Sybase (sorry I do not konw the version, but can't be too old). This is what I like to do SELECT * FROM mytable where myfield in CASE WHEN @Variable = 1 then ('test1') WHEN @Variable = 2 then ('test2') WHEN @Variable = 3 then ('test1','test2') ELSE...
https://linuxhint.com/sql-case-statement/ This tutorial mainly focuses on building a nested case statement in conjunction with the WHEN clauses. Nested CASE WHEN Statements In SQL, we can use a set of nested CASE WHEN statements in SQL to evaluate the multiple conditions and return a differe...
case语句只能代表一个值，如果你的select brno from poozfmessagebrno where upbrno = '56601'语句中返回多个值的话就会报错喽 case