Select error

Aug 4 2011 5:16 AM

        SELECT 4 AS SlNo, c.clientName AS Perticular ,NULL,convert(nvarchar(75),a.dr) AS Amount

        FROM dbo.Accounts a LEFT OUTER JOIN dbo.client c ON a.client_id=c.clientId WHERE c.cltGroupId='5' ,null,null,null

This is my select query but the following error occur

        Msg 102, Level 15, State 1, Line 25
        Incorrect syntax near ','.