SQL数据库高级教程:学习 SQL AND & OR_[SQL Server教程]
AND和OR可在WHERE子语句中把两个或多个条件结合起来。
假如所有列出的条件都成立,AND会显示一行。假如列出的条件中有一个成立,OR操作符会显示一行。
原始的表 (用在例子中的):
LastName | FirstName | Address | City | Hansen
Ola
Timoteivn 10
Sandnes
Svendson
Tove
Borgvn 23
Sandnes
Svendson
Stephen
Kaivn 18
Sandnes
实例
使用AND来显示所有姓为"Tove"并且名为"Svendson"的人:
SELECT * FROM Persons
WHERE FirstName='Tove'
AND LastName='Svendson'
结果:
LastName | FirstName | Address | City | Svendson
Tove
Borgvn 23
Sandnes
实例
使用OR来显示所有姓为"Tove"或者名为"Svendson"的人:
SELECT * FROM Persons
WHERE firstname='Tove'
OR lastname='Svendson'
结果:
LastName | FirstName | Address | City | Svendson
Tove
Borgvn 23
Sandnes
Svendson
Stephen
Kaivn 18
Sandnes
实例
我们也可以把AND和OR结合起来(使用圆括号来组成复杂的表达式):
SELECT * FROM Persons WHERE
(FirstName='Tove' OR FirstName='Stephen')
AND LastName='Svendson'
结果:
LastName | FirstName | Address | City | Svendson
Tove
Borgvn 23
Sandnes
Svendson
Stephen
Kaivn 18
Sandnes