mysql - 在 1 个 if 子句下有多个列

Question

我正在尝试编写如下查询

select 

if drophip = 1 then
0 as a,
0 as b,
1 as c,
1 as d

else if drophip = 0 then
1 as a,
1 as b,
0 as c,
0 as d

end if; 

from tabl1;

它给出了语法错误。有什么方法可以让我写出相同的内容吗？

Answer 1

试试这个:

我想你的 drophip 是 boolean 字段。

查询

select 
case
    when drophip = 1 then 0
    else 1
end as a,
case
    when drophip = 1 then 0
    else 1
end as b,
case
    when drophip = 1 then 1
    else 0
end as c,
case
    when drophip = 1 then 1
    else 0
end as d
from tabl1;