SELECT * FROM employees中的减号是什么意思WHERE -salary< 0？ [英] What does minus mean in SELECT * FROM employees WHERE -salary < 0?

问题描述

请解释工资前面的负面意义

解决方案

好的，我们试试吧。



首先尝试使用以下查询并查看结果。

  SELECT  *  FROM  employees  WHERE  salary<  0  

接下来，尝试以下操作并查看结果。

  SELECT  *  FROM  employees  WHERE  -salary<  0  

您在第一个和第二个查询结果之间看到了什么差异？

这是提示，你将从中得到答案。



让我知道。 ：）

Please explain what does minus mean in front of salary

解决方案

Okay, let's try something.

First try with the following query and see what the results.

SELECT * FROM employees WHERE salary < 0

Next, try the following and see the results.

SELECT * FROM employees WHERE -salary < 0

What differences you see between the first and second query results?
That is the hint, from which you will get the answer.

Let me know that. :)

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