Repeater with Custom Query where condition lenght limited

I have a Repeater with Custom Query. Currently, there's a WHERE Condition like this PracticeAreas = (Custom_BusinessUnit.BusinessUnitId IN (SELECT BusinessUnitId FROM Custom_BusinessUnit AS Custom_BusinessUnit_3 WHERE (ParentBusinessUnitId IN (SELECT BusinessUnitId FROM Custom_BusinessUnit AS Custom_BusinessUnit_2 WHERE (ParentBusinessUnitId IN (SELECT BusinessUnitId FROM Custom_BusinessUnit AS Custom_BusinessUnit_1 WHERE (ParentBusinessUnitId = @bu) OR (BusinessUnitId = @bu))) OR (ParentBusinessUnitId = @bu) OR (BusinessUnitId = @bu))) OR (ParentBusinessUnitId = @bu) OR (BusinessUnitId = @bu))) AND (CMS_User.UserEnabled = '1') AND (CMS_User.UserType = 1) AND (custom_certificate.DevelopManagerFlag = 1) AND (custom_certificate.AssistanceDevelopFlag = 1)WHERE condition item , Cannot insert due to field length limit. please help me