DF114: The INNER/OUTER keywords for JOIN are not specified.

The topic describes the DF114 T-SQL code analysis rule.

Category

STYLE

Message

The INNER/OUTER keywords for JOIN are not specified.

Description

To improve readability, it is recommended to explicitly specify the type of JOIN

Additional information

Explicitly specifying whether a JOIN is INNER or OUTER clarifies the relationship between the tables involved in the query and ensures that the query behaves as expected. Without this specification, it may be unclear whether the JOIN is intended to include all matching rows (INNER JOIN) or also include unmatched rows (OUTER JOIN), potentially leading to incorrect results or misunderstandings in the code.

Noncompliant code example

SELECT
  *
FROM dbo.Customer c
JOIN dbo.Language l
  ON c.LanguageId = l.LanguageId

Compliant solution

SELECT
  *
FROM dbo.Customer c
INNER JOIN dbo.Language l
  ON c.LanguageId = l.LanguageId