必需的单个SQL查询

Question

我有一个名为empdetail的表和列：

   Id  Name  Gender
    1  ABC   Male
    2  XYZ   Female
    3  PQR   Male

我想通过单个查询将每个\的Gender从Male更改为Female，从Female更改为Male

结果应为：

1 ABC Female
2 XYZ Male
3 PQR Female

Answer 1

您只需使用 CASE 声明

即可

update <table>
set Gender= case when Gender='Male' then 'Female' 
                 when Gender='Female' then 'Male' 
            end

SQL fiddle demo

Answer 2

    select id,name,
           (case when gender='Male'
                     then 'Female'
                 else 'Male' 
            end) as 'Gender' 
    from table
-------------------
   update table set gender=(case when gender='Male'
                     then 'Female' else 'Male' end)