Query executing differently with different values?

Question

I am running an exactly same query with different values in the WHERE clause. For example:

Select Col1 From TblA Where ColB = 2

Select Col1 From TblA Where ColB = 4

The query is taking much longer to run with COlB = 4. They both return almost same row counts. The CPU and the IO are same too. 

I can't figure what the issue could be? 

KK

Answer 1

Do you have index on ColB column are can you UPDATE statistics for this table?

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Answer 2

I don't have an index on the column. I will try updating the statistics. 

Answer 3

Do you have a filtered index on ColB that is helping where the value is 2 and not when it's 4? Also, ensure that the actual query isn't making use of scalar functions and it really is as simple as demonstrated above.

Answer 4

Thanks. Updating the statistics helped.

Answer 5

first you create index on colB, update the statistics and

then use below link which talks about how see exact execution times of a query 

How to check actual performance of SQL Query

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Mark this post as answer if this resolves your issue.

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