Cross database query and collation


I work for a software house and produce a SQL Server based product.  As part of the next releases upgrade, I need to release an 'upgrade database' that will be used during the upgrade process to assist with the upgrade of the 'customer database'.  Whilst I can choose the collation of the 'upgrade database' I have no way of knowing what collation the 'customer database' will use.

I need to run a query that does something like this

UPDATE <customer_database.table>
SET  <customer_database.table.field> = <upgrade_database.table.field1>
FROM <upgrade_database.table>, <customer_database.table.field>
WHERE <customer_database.table.field> = <upgrade_database.table.field2>
AND other criteria

When it executes, presumably becuase of the different collation settings, I get the error :-
Server: Msg 446, Level 16, State 9, Line 1
Cannot resolve collation conflict for equal to operation.

Note the upgrade database is a generic database that will be supplied by us as the software house.  Thus we no chance to change the upgrade database collation settings for each customer.  Obviously we cant change the customer database collation.

Hence I'm guessing there must be some clause I can add to the SQL to resolve the collation problem.

Please help...its urgent
Thanks in advance

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UPDATE <customer_database.table>
SET  <customer_database.table.field> = <upgrade_database.table.field1>
FROM <upgrade_database.table>, <customer_database.table.field>
WHERE <customer_database.table.field> = <upgrade_database.table.field2> COLLATE <Your local collation>
AND other criteria
meowshAuthor Commented:

Thanks for the very quick reply.
How do I know what the local collation is?  Presumably the local collation is the collation of the customer database which is the bit I dont know.  The upgrade runs automatically on the customer database without any user interaction.  Do I need to query the system tables to work out the collation of the customer database.  How do I do that?  Or have I misinterpretted?

You can use the collation of your own DB
I think the collation you use doesn't really matter unless your customers are in countries that use special character sets, it's just that SQL Server can't choose for you which one to use when you compare two columns with different collations.

If you want to use the customerDB's collation, you'll need to use dynamic SQL :-(

You can get default DB collation like this
select databasepropertyex(db_name(), 'Collation')

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