From: esquel@sommarskog.se   
      
   M Joomun (m.a.joomun@qmul.ac.uk) writes:   
   > I've got a search form where users can search for records from the db.   
   > The App calls a stored procedure which executes the sql below. The form   
   > has two search criteria users have requested, 'labno' and 'DateAssayReq'.   
   >   
   > The App works well for the date criteria and will find the correct   
   > record(s), but will not return any records whatever I enter for the   
   > labno, even though I know the labno exists in the db.   
   >   
   > Can someone see what I've done wrong?   
      
   The part with datalength looks funky. "DataLength(@DateAssayReq)" will   
   never be 0. It will be 3 or NULL.   
      
   Use:   
      
    WHERE (@labno IS NULL OR LabNo = @labno)   
      AND (@DateAssayReq IS NULL OR DateAssayReq = @DateAssayReq)   
      
      
   Also make sure that you pass NULL for search conditions that do not apply.   
      
   --   
   Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se   
      
   Books Online for SQL Server 2005 at   
   http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx   
   Books Online for SQL Server 2000 at   
   http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx   
      
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