如何在db2列选择查询中使用大小写

Question

我有一个表,其中有一个VARCHAR列'someid'和一些时间戳列: 'date_1', ... , date_4和'xdate_1', ... , xdate_4 我想选择其中两个依赖于"someid的价值,但没有运气,直到如今.我确信这是语法,谷歌搜索也没有帮助,因为所有的例子都与我的查询相似.

继承人我正在做的事情:

select
  case
    when someid = 1 then date_1
    when someid = 2 then date_2
    when someid = 3 then date_3
    when someid = 4 then date_4
 ,case
    when someid = 1 then xdate_1
    when someid = 2 then xdate_2
    when someid = 3 then xdate_3
    when someid = 4 then xdate_4
from mytable;

Answer 1

你忘记了 end

select
  case
    when someid = 1 then date_1
    when someid = 2 then date_2
    when someid = 3 then date_3
    when someid = 4 then date_4
  end as col1
 ,case
    when someid = 1 then xdate_1
    when someid = 2 then xdate_2
    when someid = 3 then xdate_3
    when someid = 4 then xdate_4
  end as col2
from mytable;