That's a good rule-of-thumb but doesn't address Table-Valued functions.

-Mike

>>Sergey,
>>
>>If I want to pass part of the string and return a whole string, should I use SP or UDF?
>>
>>Writing SPs is so hard for beginner!
>
>I follow this guide line...
>
>If you are writting something that is deterministic, returns a single value, and needs to be used inline in a select, sort of like you would use IsNull() or SubString() then create a function.
>
>Other than that, use an SP.
>
>Of course, rules are made to be broken.
>
>BOb