mysql query in OO Base have to avoid some compares

Question

Hello. I'm totally blank about sql, but im have to make sql query in OO Base. Query have to avoid compare, when cell in table "Search" is blank. My code dont work. I hope somebody will help me.

     SELECT "D"."Name", "D"."SName", "D"."Date of", "D"."Type", "D"."Place", "D"."Unit1", "D"."Unit2" 

    FROM "Data" AS "D", "Search" AS "S" 

    WHERE (( "D"."Name" = "S"."Name" ) OR ( "D"."Name" = '%' )) AND (( "D"."SName" = "S"."Sname" ) OR ( "D"."Sname" = '%' )) 

AND ( "D"."Date of" BETWEEN "S"."Date1" AND "S"."Date2" ) AND (( "D"."Type" = "S"."Type" ) OR ( "D"."Type" = '%' )) 
AND (( "D"."Place" = "S"."Place" ) OR ( "D"."Place" = '%' )) AND (( "D"."Unit1" = "S"."Unit1" ) OR ( "D"."Unit1" = '%' )) 
AND (( "D"."Unit2" = "S"."Unit2" ) OR ( "D"."Unit2" = '%' ))