Useful when updating a large quantities of rows from a big table

recursive_update.sql

WHILE 1 = 1
BEGIN

  UPDATE TOP(100000) A
     SET CIA = CASE 
					WHEN DS_INDICADOR = 'AUTO' THEN LEFT(RIGHT(CD_ITEM,14),3)
					WHEN DS_INDICADOR IN ('RE','RAMOS ELEMENTARES') THEN LEFT(RIGHT(CD_ITEM,10),3) 
					ELSE 0
			   END 
    FROM DB_PGC_PRODUCAO..TB_DM_INFO_GER_ANALITICO_HIST A
   WHERE CIA IS NULL

  IF @@ROWCOUNT < 1 BREAK;

END