Sql-server – Limit on number of nested IF statements

functionssql servert-sql

Is there a technical reason when T SQL gives this error?

Msg 191
Some part of your SQL statement is nested too deeply. Rewrite the query or break it up into smaller queries.

My scenario is a function with several nested IFs with ELSEs :

IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE

Changing it to the following statement doesn't raise any error:

IF (1=2) BEGIN SET @teste = 1 END
IF (1=2) BEGIN SET @teste = 1 END
IF (1=2) BEGIN SET @teste = 1 END

Best Answer

According to this Microsoft Docs page, nesting of IF statements is dependent on available memory.

On my test workstation, I was able to write and execute this, which is 189 levels deep:

declare @teste int;
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
IF (1=2) BEGIN SET @teste = 1 END ELSE
print 1

189 levels of nesting seems pretty bizarre to me, but then this is a bizarro world, lately.

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