[Sql]sql function Coalesce returns the first non-null value

Here are a few more useful examples:

First, take a look at the use of this function from MSDN, the COALESCE function (hereinafter referred to as the function), and return a non-null value for a parameter. Such as:

1. SELECT COALESCE (null, null, GETDATE ())

Since all two parameters are null, the value of the GETDATE () function is returned, which is the current time. That is, the first non-null value is returned. Since this function returns the first non-null value, there must be at least one non-null value inside the parameter, and if you use the following query, you will get an error:

 

1. SELECT COALESCE (null, null, null)

[Sql]sql function Coalesce returns the first non-null value