SQL条件语句实例

　　在SQL语句中，SQL条件语句无疑是使用最广，最常见的SQL语句之一，下面就将为您介绍几个使用SQL条件语句，供您学习参考  。

　　----查询StudentMarks 最大的前三条记录

　　select  top 3 StudentID,StudentName,Mark from StudentMarks order by Mark desc

　　----查询StudentMarks 的第30'40条记录

　　1、从前30条的后面, 取前10条

　　select top 10 * from StudentMarks where StudentID not in(select top 30 StudentID from StudentMarks)

　　2、先正序取40条, 再反序取10条

　　select top 10* from (select top 40* from StudentMarks order by Mark ) a
order by Mark desc

　　3、、利用临时表
select top 40 * into #Stm from StudentMarks order by Mark

　　select top * from #Stm  order by Mark desc

　　----查询和London同属于一个国家的城市的客户
select distinct * from customers where country in
( select country from customers where city=London)

----查询和London,Paris同属于一个国家的城市的客户
select * from customers where country in
(select country from Customers where City in (London,Paris))

----查询单价大于Dofu的产品名
select ProductName from Products where UnitPrice>
(select UnitPrice from Products where ProductName=Tofu)