SELECT * WHERE var == [众多选择之一]

Question

在 MySQL 中，我可以用 OR 指定替代匹配：

SELECT * FROM table WHERE var = 1 OR var = 2

当备选方案很多时，像这样一一罗列会显得很麻烦。有没有办法，我可以给出一个列表、向量或值数组？有点像这个伪代码：

SELECT * FROM table WHERE var IN {1, 2, 5, 11, 45}

Answer 1

您可以用圆括号而不是大括号指定 IN。

SELECT * FROM table WHERE var IN (1, 2, 5, 11, 45)

Answer 2

MySQL 中的第一个 equality/comparison 运算符是 = 而不是 ==.

是的你可以通过引入 IN 子句来达到同样的目的。但是您的语法不符合 MySQL 标准。应该是：

SELECT * FROM table WHERE your_column IN (1,2,5,11,45)

注：

Use IN.

IN will use an index.

OR will (afaik) not use an index.

Also, and this point is not to be sneezed at, the IN version:

uses less code

is easier to maintain

is easier to understand

For those reasons alone I would be prepared suffer a little performance to gain code quality, but you actually gain performance too.

OR VS IN

SELECT * WHERE var == [众多选择之一]

SELECT * WHERE var == [one of many alternatives]

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