Duplicate records in SQL - Oracle

Question

Good morning, I’m new here and I’ve got a boring problem. Distinct does not solve my problem because the duplication is due to the fact that I had to make the relationship with other tables to seek information. SQL returns me two values with different supervisors for the same IDCALLED, as I do to display only one IDCALLED so as not to duplicate the records?

SELECT ch.idchamado,su.nome AS nomesupervisor,
  e.nome,
  ch.dataabertura,
  ch.datafechamento,
  ta.desctipoassunto
FROM sase_chamado ch
LEFT JOIN vw_app_consulta_escolas e
ON ch.idpj = e.idpessoa_juridica
LEFT JOIN sase_tipoassunto ta
ON ta.idtipoassunto = ch.idtipoassunto
LEFT JOIN sase_escolasusuario eu
ON eu.idpj = ch.idpj
INNER JOIN sase_usuario su
ON eu.idusuario = su.idusuario
WHERE ch.dataabertura BETWEEN to_date('01/01/16', 'dd/mm/yy') AND to_date('30/07/16', 'dd/mm/yy')
ORDER BY su.nome,
  e.nome,
  ta.desctipoassunto

the darn duplicity is of that kind here:

Answer 1

When we have we want only one line without caring about the content we use MIN or MAX and group what is equal.

SELECT ch.idchamado AS idchamado, 
  MIN( su.nome ) AS nomesupervisor,
  e.nome,
  ch.dataabertura,
  ch.datafechamento,
  ta.desctipoassunto
FROM sase_chamado ch
LEFT JOIN vw_app_consulta_escolas e
ON ch.idpj = e.idpessoa_juridica
LEFT JOIN sase_tipoassunto ta
ON ta.idtipoassunto = ch.idtipoassunto
LEFT JOIN sase_escolasusuario eu
ON eu.idpj = ch.idpj
INNER JOIN sase_usuario su
ON eu.idusuario = su.idusuario
WHERE ch.dataabertura BETWEEN to_date('01/01/16', 'dd/mm/yy') AND to_date('30/07/16', 'dd/mm/yy')
GROUP BY 
  ch.idchamado 
  e.nome,
  ch.dataabertura,
  ch.datafechamento,
  ta.desctipoassunto
ORDER BY su.nome,
  e.nome,
  ta.desctipoassunto