sql变量从select,insert获取值两种情况的操作

　　下面将为您介绍sql变量从select,insert获取值的单值情况及记录集情况的操作，供您参考，希望对您学习sql变量会有所帮助  。

　　use Northwind

　　--整形sql变量的赋值

　　declare @addr int
set @addr = (select sum(power(2,cast(EmployeeID as integer))) as addr from employees )
print 员工id的平方和为：+cast(@addr as varchar(10))

　　--浮点数sql变量的赋值

　　declare @total float
set @total = (select sum(freight) as freight from Orders)
print 所有商品的总运费为：+cast(@total as varchar(10))

　　--记录集sql变量的赋值

　　declare @tb table(id int,name varchar(20),country varchar(20))
insert into @tb select employeeid,firstname+ +lastname,country from employees
select * from @tb
select a.name,b.customerId,b.freight from @tb a,orders b where a.id=b.employeeid

　　关键点：单值情况下，select一定要用括号