About the null judgment problem in different versions of SQL Server

Recently done a small test site, where there is a page, the page load need to calculate a number of

There is a row of SQL statements,

Select SUM (FileSize) from [File] where [email protected], everything is OK during native testing

But did not expect is because of this sentence SQL statement, tossing the afternoon, the machine vs2012+sqlserver2008

When you deploy to the server, you always get an error when you go to this page

Check the good information, before returning may be due to the SQL Server version

Finally, find a workaround: Replace the SQL statement with the following:

Select IsNull (SUM (isnull (FileSize, 0)), 0) from [File] where [email protected]

Each step is judged to be empty

Because SQL Server version is too low, some features do not support, it will cause a variety of inexplicable errors

Put it in here and share it with you.

Beginners are not easy, I hope you master a lot of guidance

About the null judgment problem in different versions of SQL Server