SQL语句

子查询 加一列作为统计



select UserName,Month,Salary,


Cummulation=(

select SUM(Salary)


from


User_Salary i

where


i.UserName=o.UserName and i.Month<=o.Month


)

from User_Salary o

order by 1,2


select


A.*,B.*

from

User_Salary A inner join User_Salary B


ON

A.UserName = B.UserName

where

B.Month <= A.Month


order by 1,2

select

A.UserName,A.Month,MAX(A.Salary) as Salary,SUM (B.Salary) as Accumulation


from

User_Salary A inner join User_Salary B


ON


A.UserName = B.UserName

where


B.Month <= A.Month


group by


A.UserName,A.Month


order by


A.UserName,A.Month

查询特殊符号ESCAPE定义转义符
在使用LIKE关键字进行模糊查询时，“%”、“_”和“[]”单独出现时，会被认为是通配符。为了在字符数据类型的列中查询是否存在百分号（%）、下划线（_）或者方括号（[]）字符，就需要有一种方法告诉DBMS，将LIKE判式中的这些字符看作是实际值，而不是通配符。关键字ESCAPE允许确定一个转义字符，告诉DBMS紧跟在转义字符之后的字符看作是实际值。

//查询10%

select * from deptre where deptname LIKE '%10!%%' ESCAPE '!'

//查询_

select * from deptre where deptname LIKE '%!_%' ESCAPE '!'
select * from deptre where deptname LIKE '%!_!%%' ESCAPE '!'