> Consider the following WHERE clause:
>
> ...WHERE (Col = 1) OR (Col IN (SELECT OtherCol FROM OtherTable))
>
> Would it be different performance-wise from the following:
>
> ...WHERE Col IN (SELECT 1 UNION SELECT OtherCol FROM OtherTable)
>
>
> Thank you.

> Consider the following WHERE clause:
>
> ...WHERE (Col = 1) OR (Col IN (SELECT OtherCol FROM OtherTable))
>
> Would it be different performance-wise from the following:
>
> ...WHERE Col IN (SELECT 1 UNION SELECT OtherCol FROM OtherTable)

Erland Sommarskog wrote:
> Sericinus hunter (serhunt@flash.net) writes:
>> Consider the following WHERE clause:
>>
>> ...WHERE (Col = 1) OR (Col IN (SELECT OtherCol FROM OtherTable))
>>
>> Would it be different performance-wise from the following:
>>
>> ...WHERE Col IN (SELECT 1 UNION SELECT OtherCol FROM OtherTable)
>
> There is a chance that SQL Server will avoid the subquery if Col is 1,
> if you use the former. In any case, being obscure is rarely a good
> idea.