oracle-sql操作

 1、oracle-sql查询90天以前的数据

select * from t_test where create_Date < sysdate-90;

2、oracle-sql更新表字段为关联表中的字段

  a、b表都有id字段，status字段，需要将a表的status字段更新到b表的status字段上去

update table_b b set b.status = 
(select a.status from table_a a where a.id=b.id and a.status is not null)
where exists 
(select 1 from table_a a where a.id=b.id and a.status is not null)