oracle sql 记录存在则更新，不存在则插入

MERGE <hint> INTO <table_name>

USING <table_view_or_query>

ON (<condition>)

WHEN MATCHED THEN <update_clause>

DELETE <where_clause>

WHEN NOT MATCHED THEN <insert_clause>
[LOG ERRORS <log_errors_clause> <reject limit <integer | unlimited>]; 

MERGE INTO USERINFO a
USING (
  SELECT '1' as UNAME
  FROM dual
  ) b
ON (a.UNAME = b.UNAME)
WHEN MATCHED THEN
  UPDATE SET a.ADDR = 'ddd', a.UTC = 1234567
WHEN NOT MATCHED THEN
  INSERT (a.ADDR, a.UTC, a.UNAME) VALUES ('aaa', 7654321, '1');