mysqlcasewhen理解和应用 [数据库教程]

database

简单函数
CASE [col_name] WHEN [value1] THEN [result1]…ELSE [default] END new_col_name

-- 枚举

select

t_name,

case t_name

when‘张三‘

then‘严肃‘

when‘李四‘

then‘凶狠‘

when‘王五‘

then‘和蔼‘

end t_character

from `teacher`

搜索函数
CASE WHEN [expr] THEN [result1]…ELSE [default] END new_col_name

-- 搜索判断
select
*,
case
when s_score <60
then‘不及格‘
when s_score >=60and s_score <80
then‘中等‘
when s_score >=80
then‘优秀‘
end score_type
from `score`

mysql case when 理解和应用