问ORA-44002函数体上的无效对象名称

EN

DECLARE 
      X VARCHAR2(32767);
    BEGIN
      X := '
      SELECT to_char(days.n, ''DD/MM/YYYY HH24'') as name,
             NVL(ROUND(AVG(s1.HIGH),2),-1) HIGH
      FROM  (SELECT TO_DATE('''||:P8_DATE_DEBUT||''', ''DD/MM/YYYYHH24'')+(level-1)/TO_NUMBER('''||:P8_ECHELLE||''') as n
             FROM   dual
             CONNECT BY level <= TO_DATE('''||:P8_DATE_FIN||''', ''DD/MM/YYYYHH24'')+1-TO_DATE('''||:P8_DATE_DEBUT||''', ''DD/MM/YYYYHH24''))*TO_NUMBER('''||:P8_ECHELLE||''')      
            ) days
            LEFT OUTER JOIN
            (SELECT trunc(RAW_DATE, '''||:P8_TRUNC||''') as HO,
                    NVL(ROUND(AVG(VALID_VALUE),2), 0) as HIGH
             FROM  '||
                   dbms_assert.sql_object_name('SAFEGE.MSR_'||NVL(:P8_ECHELLE_EMMA,'4245')) -- NVL better than COALESCE for a simple Null check
                   ||'@EMMASAFE.NTSIVOA'
                   ||'
             WHERE RAW_DATE >= TO_DATE('''||:P8_DATE_DEBUT||''', ''DD/MM/YYYY'')  -- avoiding BETWEEN means less messing about with time components
             AND   RAW_DATE <  TO_DATE('''||:P8_DATE_FIN||''', ''DD/MM/YYYY'')+1  -- just need to use less than target date+1 instead
             AND   VALIDITY = 1
             GROUP BY trunc(RAW_DATE, '''||:P8_TRUNC||''') 
            ) s1
            ON days.n = S1.HO
      GROUP BY days.n
      ORDER BY days.n';
      RETURN X;
    END;