This query deletes a specified phone number from all records in the contact table.
BEGIN TRANSACTION UPDATE Contact SET homePhone = CASE WHEN homePhone = '(555)555-5555' THEN NULL ELSE homePhone END, workPhone = CASE WHEN workPhone = '(555)555-5555' THEN NULL ELSE workPhone END, cellPhone = CASE WHEN cellPhone = '(555)555-5555' THEN NULL ELSE cellPhone END WHERE homePhone = '(555)555-5555' OR workPhone = '(555)555-5555' OR cellPhone = '(555)555-5555' ROLLBACK TRANSACTION --COMMIT TRANSACTION