查询无效的同义词
SELECT S.OWNER as SYN_OWNER, S.SYNONYM_NAME as SYN_NAME,
S.TABLE_OWNER as OBJ_OWNER, S.TABLE_NAME as OBJ_NAME,
CASE WHEN O.OWNER is null THEN 'MISSING' ELSE O.STATUS END as OBJ_STATUS,O.STATUS
FROM DBA_SYNONYMS S