Sql Server - Using Collation

Question

I am using below query in which I need to specify collation hint to avoid collation issues across databases as this query uses tables from 2 databases.

Msg 468, Level 16, State 9, Line 12 Cannot resolve the collation conflict between "Latin1_General_CS_AI" and "Latin1_General_CS_AS" in the equal to operation.

Currently I am getting above error for collation conflicts when I run some of the queries which uses different databases with different collations:

Delete from table1 where oldcolumn in
(
select newcolumn from Database2.dbo.table2
where invoiceid = @invno
and complete = 0
)

I changed the query to include collation hint as below:

Delete from table1 where oldcolumn COLLATE SQL_Latin1_General_CP1_CS_AS in
(
select newcolumn from Database2.dbo.table2
where invoiceid = @invno
and complete = 0
)

1. Will above query solve the problem of collation?
2. Is it same to specify collate hint on left or right of operator (eg "=" operator)?
3. Can query like invoiceid = @invno ever generate runtime collation conflit error?

Note: I am asking this question as I do not have access to any of the above 2 databases and the script will be run on actual databases.

Answer 1

Use Below Query :

DELETE FROM Table1
WHERE Table1.ID IN (
                SELECT Table1.ID
                FROM Table1
                INNER JOIN Database2.dbo.Table2 Table2 ON Table2.NewColumn = Table1.OldColumn COLLATE SQL_Latin1_General_CP1_CS_AS
                WHERE   Table2.invoiceid = @invno
                    AND Table2.complete = 0
                )