SQL指南－AND & OR

AND & OR

AND 和OR 在WHERE子句中连接两个或更多的条件。

AND 运算符当所有条件为真时列出行记录。运算符当任一条件为真时列出行记录。

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原始表 (用于示例)

LastName	FirstName	Address	City
Hansen	Ola	Timoteivn 10	Sandnes
Svendson	Tove	Borgvn 23	Sandnes
Svendson	Stephen	Kaivn 18	Sandnes

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示例

使用AND显示每个first name等于"Tove"，和last name等于"Svendson"：

SELECT * FROM Persons
            WHERE FirstName='Tove'
            AND LastName='Svendson'

返回结果：

LastName	FirstName	Address	City
Svendson	Tove	Borgvn 23	Sandnes

示例

使用OR来显示每个first name等于"Tove"，或者last name 等于 "Svendson"：

SELECT * FROM Persons
            WHERE firstname='Tove'
            OR lastname='Svendson'

返回结果：

LastName	FirstName	Address	City
Svendson	Tove	Borgvn 23	Sandnes
Svendson	Stephen	Kaivn 18	Sandnes

示例

我也可以联合AND 和OR （使用圆括号来联合表达式）

SELECT * FROM Persons WHERE
            (FirstName='Tove' OR FirstName='Stephen')
            AND LastName='Svendson'

Result:

LastName	FirstName	Address	City
Svendson	Tove	Borgvn 23	Sandnes
Svendson	Stephen	Kaivn 18	Sandnes