Did you know that TempDB's collation isn't necessarily the same as your database's collation? Do you care?
Why, yes, you do.
- We all know that you can set the default collation for a SQL Server instance when you install it, right?
- We all know that you can set the default collation for a database when you create it, right? (and it defaults to the instance's setting)
- We mostly all know that you can set the collation for a table when you create it, right? (and it defaults to the database's setting)
- Some of us even know that you can set the collation for an individual column, right? (and it defaults to the table's setting)
Now, quick, what happens to temporary tables? They're created in
TempDB, of course. What collation is applied to those tables? The default collation for
TempDB, of course.
Oh... I see, so if my instance is case insensitive (most are), and my
TempDB hasn't been
ALTERed to a specific collation (most haven't), then when I create a temporary table from my case-sensitive database I am about to be surprised in a very subtle way... It's as easy as
CREATE TABLE #temp COLLATE database_default to prevent this.
Kimberly L. Tripp has the details, it is a must-read: Changing Database Collation and dealing with TempDB Objects.