SQL Server: Select Top 0?

Question

We just came across this in an old production stored proc (there is a lot more going on in here, but this is in one leg of its logic). Why would someone ever select top 0 ro

Answer 1

Use this to create a temporary table where the collation of your DB and TEMPDB may differ.

SELECT TOP(0) column INTO #temp FROM [mytable]

Produces a temp table with same collation as my table. This then means

SELECT * FROM #temp T INNER JOIN [mytable] M ON M.column=T.column

Does not fail due to a collation error.

Answer 2

By doing this, you have an empty resultset with all columns instead of no result. If the program using the stored procedure expects certain columns, it would crash otherwise.

Answer 3

You could use this to grab the column names.

Answer 4

I have mostly used it when creating temp tables from an existing DB table - without any data. The following is more reliable though than using top.

SELECT * FROM <table_name> LIMIT 0;

Answer 5

Let me provide an additional use:

If you want a message printed in the output rather than in messages, you could use

select top 0 0 'Your message here'

instead of

print 'Your message here'

Answer 6

You can use this to check if your SQL syntax is correct without loading any data.