How to avoid duplicates for an result set

Question

how to avoid the duplicate rows for the below query
SELECT  to_char(grecode (titleid)) gre_code, to_char(toeflcode (titleid)) toefl_code,titleid
          FROM (SELECT DISTINCT TO_CHAR
                                   (UPPER (TRIM (get_clob_value (table_name,
                                                                 KEY
                                   ) RESULT,
                                titleid
                           FROM mcp_specifications a JOIN mcp_title_specifications b
                                ON a.specificationid = b.specificationid
                                JOIN mcp_titles c ON b.titleid = c.titleid
                          WHERE b.is_parent = 'F'
                            AND UPPER (TRIM (c.university_state)) =
                                                          UPPER (TRIM ('USA'))
                            AND TO_CHAR (get_clob_value (table_name, KEY)) IS NOT NULL
                            AND UPPER (TRIM (SPECIFICATION)) IN
                                                   (UPPER (TRIM ('program'))))
         WHERE UPPER (TRIM (RESULT)) = UPPER (TRIM ('COMPUTER SCIENCE'))
      ORDER BY RESULT ASC;the output of the query would be
gre_code    toefl_code   titleid
402             78             5518
402             78             5519
402             78             5520
402             78             5521the output should be
402 78 any titleid

Answer 1

Some simplified code:
SELECT grecode(titleid) gre_code,
       toeflcode(titleid) toefl_code,
       min(titleid) titleid
FROM   (SELECT DISTINCT TO_CHAR(UPPER(TRIM(get_clob_value(table_name,KEY)))) RESULT,
               titleid
        FROM   mcp_specifications a
               JOIN mcp_title_specifications b
                    ON a.specificationid = b.specificationid
               JOIN mcp_titles c
                    ON b.titleid = c.titleid
        WHERE  b.is_parent = 'F'
        AND    UPPER(TRIM(c.university_state)) = 'USA'
        AND    TO_CHAR (get_clob_value (table_name, KEY)) IS NOT NULL
        AND    UPPER(TRIM(SPECIFICATION)) = 'PROGRAM')
WHERE  UPPER(TRIM(RESULT)) = 'COMPUTER SCIENCE'
GROUP BY grecode(titleid),
         toeflcode(titleid)Please note that applying functions like UPPER and TRIM on a string literal can and should be avoided.
For example:
UPPER(TRIM('USA')) = 'USA'Why force the database to do both an UPPER and a TRIM on something that can just be represented in uppercase with no surrounding spaces? It's a waste of time.