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SELECT LPAD(FC5DIASTOHMS((DTAHORAFIMGER - DTAHORAINIGER), 'H'), 2, '0') || ':' ||
       LPAD(FC5DIASTOHMS((DTAHORAFIMGER - DTAHORAINIGER), 'M'), 2, '0') AS TEMPO
  FROM (SELECT MIN(A.DTAHORAINIGER) DTAHORAINIGER,
               MAX(A.DTAHORAFIMGER) DTAHORAFIMGER
          FROM EFD_LOG_GERACAO A
         WHERE A.SEQGERACAO = pnSeqGeracao
         ORDER BY A.SEQUENCIA);

SELECT DISTINCT A.SEQGERACAO, 
                A.DTAGERACAO
  FROM EFD_LOG_GERACAO A
 WHERE A.CODIGO_LAYOUT = pnCodigoLayout
   AND A.NROEMPRESA = pnNroEmpresa
 ORDER BY A.DTAGERACAO DESC