分段函数(case)
##分段函数case.
##员工表中,根据薪资不一样,给不一样的评论
>4000,NB666
>3000,NB66
>2000,NB6
<2000,ZZ
============================================
select
sal,
case
when sal>4000 then 'NB666'
when sal>3000 then 'NB66'
when sal>2000 then 'NB6'
else 'zz'
end as pj
from
emp;