一、CASE field WHEN value THEN value WHEN ... THEN ... ELSE ...
sample: www.2cto.com
Sql代码
select CASE usertype WHEN 1 '管理员' WHEN 2 THEN '策划' WHEN 3 THEN '测试员' ELSE '未定义' AS usertype FROM users
二、IF( exp, value, value)
Sql代码
IF (1 = 1,'A','B')