笔记

PL/SQL导入sql文件：1.点击新建 2.命令窗口 3.@+回车 4.选择导入的sql文件

Create table test_table as select *from dev_table----复制一个临时表（并且复制表里的数据）

Create table test_table as select *from dev_table where 1=2----复制一个临时表（不复制表里的数据）

insert into table1 select * from table2 复制一个表的数据(表结构一样)

insert iinto table1 (字段1，字段2) select  字段1，字段2 from table2 ----复制表的数据（表结构不一样）

with unit as (select * from vw_org) select * from unit -----临时表

with t1 as (select * from dual),t2 as (select * from dual) select t1.*,t2.* from t1 inner join t2 on t1.id=t2.id ---两个临时表关联

select status from user_indexes where index_name='IDX_SYS CONS_O_CI…PL_SQL查询数据库字段的索引是否有效

删除数据库的重复数据
查询及删除重复记录的SQL语句
1、查找表中多余的重复记录，重复记录是根据单个字段（Id）来判断
select * from 表 where Id in (select Id from 表 group by Id having count(Id) > 1)

2、删除表中多余的重复记录，重复记录是根据单个字段（Id）来判断，只留有rowid最小的记录
DELETE from 表 WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 GROUP BY id HAVING COUNT(*) > 1);

3、查找表中多余的重复记录（多个字段）
select * from 表 a
where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1)
4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录
delete from 表 a
where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1)
and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1)
5、查找表中多余的重复记录（多个字段），不包含rowid最小的记录
select * from 表 a
where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1)
and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1)