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This article gives you a detailed introduction to SqlServer null handling. Most of the knowledge points are often used by everyone, so I will share them for you as a reference. Let's follow the editor and have a look.

In the database, if a column does not specify a value, then the value is null, the null in this null and C#, and the null in the database

"I don't know", not "no".

So the select null+1 result is null, because the result of "don't know" plus 1 is still "don't know".

SELECT * FROM T_Employee WHERE FNAME=null

SELECT * FROM T_Employee WHERE FNAME invalid null

No results were returned because the database "doesn't know" either.

Is null and is not null are used in SQL to determine null values:

SELECT * FROM T_Employee WHERE FNAME is null

DbNull.Value for processing in C #

SELECT * FROM T_Employee WHERE FNAME is not null

On the SqlServer null value processing to share here, I hope that the above content can be of some help to you, can learn more knowledge. If you like this article, you might as well share it for more people to see.

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