DF204: IN predicate with a subquery is used.

Last modified: May 28, 2025

The topic describes the DF204 T-SQL code analysis rule.

Message

IN predicate with a subquery is used.

It is recommended to avoid using the IN predicate with a subquery and opt for the EXISTS predicate instead for improved query performance.

SELECT c.CustomerName FROM dbo.Customer c
WHERE c.CustomerId IN (SELECT r.CustomerId FROM dbo.Receipt r)
GO

SELECT c.CustomerName FROM dbo.Customer c
WHERE EXISTS (SELECT * FROM dbo.Receipt r WHERE r.CustomerId = c.CustomerId)
GO

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