SELECT SIGITENS.CODCONTA,
 PLACON2011.DESCRICAO,
 SIG.DESCRICAO SIGDESCRICAO,
  SIGITENS.LIMITE LIMITE,
   PLACON2011.SDO_JAN VALOR,
    ( CASE WHEN ((SIGITENS.LIMITE ) < PLACON2011.SDO_JAN) THEN ((SIGITENS.LIMITE ) - PLACON2011.SDO_JAN) ELSE 0 END ) EXCECAO
    FROM SIGITENS, SIG
    INNER JOIN PLACON2011
    ON PLACON2011.CODEMPRESA = SIGITENS.CODEMPRESA
    AND PLACON2011.CODCONTA = SIGITENS.CODCONTA
    WHERE SIGITENS.CODEMPRESA = 1
    AND SIGITENS.CODSIG = 1
    ORDER BY SIGITENS.CODSIG