...sum(case when a.city

精选知识

举个例子:比如

a中 当a.city_id in (34, 33, 32) 返回的是1

b中 当a.city_id in (34, 33, 32) 时,是返回的2 你这又是个sum()函数.当然结果不一样了.

其他类似问题

问题1：求救oracle case when用法我现在一张表stuinfo（sid ,sname）结构如下1 ,null2 ,张三现在我想要用以个语句查询出下表的结果1,用户名为空2,张三我这样写不对 设能告诉我那错了帮忙修正过来select case w

1、不用CASE,用NVL函数即可：

SELECT sid,NVL(sname,'姓名为空' ) from stuinfo;

2、CASE:

SELECT sid,

CASE WHEN snameIS NULL THEN '姓名为空' ELSE sname END CASE

from stuinfo;

问题2：oracle 关于 case when order by case when paiming is null then 99 else paiming end asc 这句话有什么问题 else 等于自己这样写是不是有问题 改怎么写[数学科目]

只有paiming 是数字类型的,这个语句是没有问题的.

你这么写有什么错误了吗?

或者直接：

order by nvl(paiming,99)

问题3：mysql的case when语句转oraclewhere子句条件如下：where a.xxx = 'asdf' and (case when (b.i like '%0%') then truewhen (b.i like '%1%') then c.creatorCode = #code#when (b.i like '%2%') then (d.createDept = #dept# and #flag# = 1)else false end)[数学科目]

oracle也有case when的语法,照办就行,不过用在where条件中,需要有返回值的比较.

这是根据你提供的语句修改,给你提供一个参考吧：

where a.xxx = 'asdf' and (

case

when (b.i like '%0%') then true

when (b.i like '%1%') and c.creatorCode = #code# then true

when (b.i like '%2%') and (d.createDept = #dept# and #flag# = 1) then true

else false

end) = true

这是按照我的业务理解写的

where a.xxx = 'asdf' and (

case

when (b.i like '%0%') then 1

when (b.i like '%1%') and c.creatorCode = #code# then 2

when (b.i like '%2%') and (d.createDept = #dept# and #flag# = 1) then 3

else 4

end) = 1 -- (根据反回结果来过滤数据）