Understanding UNION and UNION ALL in SQL Server
A short look at the differences in UNION and UNION ALL in a SELECT query.
2025-04-07
4,323 reads
UNION ALL
UNION vs. UNION ALL in SQL Server
Sometimes there is a need to combine data from multiple tables or views into one comprehensive dataset. This may be for like tables within the same database or maybe there is a need to combine like data across databases or even across servers. I have read about the UNION and UNION ALL commands, but how do these work and how do they differ?
2019-12-05
UNION ALL Optimization
Paul White digs into row goals as he explains some interesting and inconsistent behavior with UNION ALL queries in SQL Server.
2017-06-13
5,896 reads
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Question of the Day
Fixing the Error
On SQL Server 2025, I have a database that has this collation: SQL_Latin1_General_CP1_CI_AS. I decide I want to run this code:
SELECT UNISTR('*3041*308A*304C*3068 and good night', '*') AS 'A Classic';
I get this error:Msg 9844, Level 16, State 4, Line 24 The char/varchar input type uses an unsupported collation. Only a UTF8 collation is supported with char/varchar input type in UNISTR function.What is the easiest way to fix this error? See possible answers