黑马程序员---SQL Server中的函数以及传智播客自学SQL视频笔记

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字符串函数

日期函数

数学函数

系统函数

 select cast('2012-4-15' as datetime),cast('123' as int)+123,
convert(datetime,'2012-4-16'),convert(int,'456')+456;

select datepart(year,cast('2018-1-8' as datetime))
select isnull(FName,'佚名') as 姓名  from T_Employee

select FName,
(
case FLevel
when 1 then 'VIP客户'
when 2 then '高级客户'
when 3 then '普通客户'
else '未知类型客户'
end
)  客户类型
from T_Custom

select FName ,
(
case
when FSalary<2000 then '低收入'
when FSalary>=2000 and FSalary<=5000 then '中等收入'
when FSalary >5000 then  '高收入'
else '未知'
end
)as 收入水平
from T_Employee

 

SELECT sname,

SUM(CASE

WHEN score='胜' THEN 1   ELSE 0   END) AS 胜 ,

SUM(CASE                       

WHEN score='负' THEN 1 ELSE 0 END) AS 负

FROM test3

GROUP BY sname;

select MName,
sum(
case
when Mlogic=N'胜' then 1
else 0
end
) as 胜,
sum(
case
when MLogic=N'负' then 1
else 0
end
) as 负
from T_Match
group by MName

select FNumber,
(
case
when FAmount>=0 then FAmount
else 0
end
) as 收入 ,
(
case
when FAmount<0 then abs(FAmount)
else 0
end
) as 支出
from T_Money

CREATE TABLE CallRecords
(
id INT IDENTITY(1,1) PRIMARY KEY,
CallNumber CHAR(3) NOT NULL,
TelNum CHAR(20),
StartDatetime DATETIME,
EndDatetime DATETIME
)

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