The topic describes the DF031 T-SQL code analysis rule.
DEPRECATED
Non-ANSI standard join is used.
It is recommended to use the ANSI-standard join syntax and explicitly specify the type of join you are using.
SELECT *
FROM dbo.Order o, dbo.OrderItems oi
WHERE o.OrderId=oi.OrderId
SELECT *
FROM dbo.Order o JOIN dbo.OrderItems oi
ON o.OrderId=oi.OrderId