oracle小技巧

1.时间处理

获取当前时间：sysdate
获取当前时间前一天：sysdate - interval '1' day

2.将一张表中的数据同步到另一张表中

MERGE INTO T T1
 
USING (SELECT '1001' AS a,2 AS b FROM dual) T2
 
ON ( T1.a=T2.a)
 
WHEN MATCHED THEN
 
  UPDATE SET T1.b = T2.b
 
WHEN NOT MATCHED THEN 
 
  INSERT (a,b) VALUES(T2.a,T2.b);