mysql case when 理解和应用

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 >= 60 and 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

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