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。
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 |
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 |