AND 和 OR 可在 WHERE 子句中把 两个或多个条件 结合起来。
表:
LastName |
FirstName |
Address |
City |
Adams |
John |
Oxford Street |
London |
Bush |
George |
Fifth Avenue |
New York |
Carter |
Thomas |
Changan Street |
Beijing |
Carter |
William |
Xuanwumen 10 |
Beijing |
AND 实例
使用 AND 来显示所有 姓为 "Carter" 并且 名为 "Thomas" 的人:
SELECT * FROM Persons WHERE FirstName='Thomas' AND LastName='Carter'
结果:
LastName |
FirstName |
Address |
City |
Carter |
Thomas |
Changan Street |
Beijing |
OR 实例
使用 OR 来显示所有 姓为 "Carter" 或者 名为 "Thomas" 的人:
SELECT * FROM Persons WHERE firstname='Thomas' OR lastname='Carter'
结果:
LastName |
FirstName |
Address |
City |
Carter |
Thomas |
Changan Street |
Beijing |
Carter |
William |
Xuanwumen 10 |
Beijing |
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='Thomas' OR FirstName='William')
AND LastName='Carter'
结果:
LastName |
FirstName |
Address |
City |
Carter |
Thomas |
Changan Street |
Beijing |
Carter |
William |
Xuanwumen 10 |
Beijing |