Question

SQL 中 where 条件中 in 后面 加 CASE WHEN 语句 报错

select new_projectsize, count(cifno)
from (select distinct (a.cifno) as cifno,
b.new_projectsize as new_projectsize
from cr_xdall a, cr_corp_inf b
where substr(a.mon_date, 1, 6) = '201212'
and xdflag = '1'
and opn_br_no in
(case when '1' = '1' then
(select brno from poozfmessagebrno where upbrno = '56601') else
'50000' end)
and a.cifno = b.cifno
and bal != '0'
group by b.new_projectsize, a.cifno)
group by new_projectsize;

Answer 1

.....老大看清楚你用的有问题，=是赋值不是判断==才是判断，'1' = '1'把一个字符串赋值给另一个字符串没有意义，而且似乎也不符合语法啊，这种错误似乎很低级，我这里没有现成的调试工具，你改了这个错误看看，如果还有把错误贴一下
CASE WHEN 语句 报错 可能就是因为你给了一个错误的判断条件，他的结果也不是一个布尔值啊

Answer 2

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

追问

我现在想要得到多个值，在in里做条件，该如何实现此方案

追答

那就看你为什么用case了，如果只是做选择的话，可以用if else写两组语句进行切换

Answer 3

and opn_br_no in
(case when '1' = '1' then
(select brno from poozfmessagebrno where upbrno = '56601') else
'50000' end)

修改为:

and opn_br_no in
( select
case when '1' = '1' then brno else '50000' end
from
poozfmessagebrno
where upbrno = '56601'
)

Answer 4

先将select brno from poozfmessagebrno where upbrno = '56601'结果赋值给一个变量再去试一下语句