Question

I have a search query that I’m inheriting and attempting to optimize. I am curious to hear if anyone has any best practices and recommendations for such. The production server is still SQL Server 2000 also.

The query is an advanced customer search stored procedure that accepts 5 different search criteria parameters (i.e. first name, last name, address, phone, etc.) to search a multi-million record table. There are indexes on all joined columns and columns in the WHERE clause. In addition, the initial query dumps the records into a table variable for paging capacity.

INSERT INTO   @tempCustTable (CustomerID, FirstName, LastName, City, StateProvince, Zip, PhoneNumber) SELECT  DISTINCT cu.CustomerID, cu.FirstName, cu.LastName, a.City, a.StateProvince, a.Zip, p.PhoneNumber FROM Customer cu WITH(NOLOCK) LEFT OUTER JOIN Address a WITH(NOLOCK) ON cu.CustomerID = a.CustomerID LEFT OUTER JOIN Phone p WITH(NOLOCK) ON cu.CustomerID = p.CustomerID WHERE  (cu.LastName = @LastName OR cu.LastName LIKE @LastName + '%')  AND (@FirstName IS NULL OR cu.FirstName = @FirstName OR cu.FirstName LIKE @FirstName + '%') AND (@StateProvince = '' OR a.StateProvince LIKE @StateProvince) AND (@City = '' OR a.City LIKE @City + '%') AND (@Zip = '' OR a.Zip = @Zip OR a.Zip LIKE @Zip + '%') ORDER BY cu.LastName, cu.FirstName 

Does anyone have any recommendations on how I could improve the performance of the query?

Answer 1

isn’t this whole line

AND (@Zip = '' OR a.Zip = @Zip OR a.Zip LIKE @Zip + '%') 

the same as this

AND (a.Zip LIKE @Zip + '%') 

for sure

AND (a.Zip LIKE @Zip + '%') 

it is the same as

a.Zip = @Zip OR a.Zip LIKE @Zip + '%'