Question

I have a Stored Proc which performs search on records.

The problem is that some of the search criteria,which are coming from UI, may be empty string.
So, when the criteria not specified, the LIKE statement becomes redundant.

How can I effectively perform that search or Sql Server? Or, Does it optimize LIKE(‘%%’) query since it means there is nothing to compare?

The Stored proc is like this:

ALTER PROC [FRA].[MCC_SEARCH]
@MCC_Code varchar(4),
@MCC_Desc nvarchar(50),
@Detail nvarchar(50)
AS
BEGIN             
       SELECT
             MCC_Code,
             MCC_Desc,
             CreateDate,
             CreatingUser

       FROM
              FRA.MCC (NOLOCK)
       WHERE
             MCC_Code LIKE ('%' + @MCC_Code + '%')
             AND MCC_Desc LIKE ('%' + @MCC_Desc + '%')
             AND Detail LIKE ('%' + @Detail + '%')
       ORDER BY MCC_Code

END

Answer 1

The short answer is – no
The long answer is – absolutely not

Does it optimize LIKE(‘%%’) query since it means there is nothing to compare?

The statement is untrue, because there is something to compare. The following are equivalent

WHERE column LIKE '%%'
WHERE column IS NOT NULL

IS NOT NULL requires a table scan, unless there are very few non-null values in the column and it is well indexed.

EDIT

Resource on Dynamic Search procedures in SQL Server:
You simply must read this article by Erland Sommarskog, SQL Server MVP http://www.sommarskog.se/dyn-search.html (pick your version, or read both)

Otherwise if you need good performance on CONTAINS style searches, consider using SQL Server Fulltext engine.