Oracle常用語句（建議收藏）

1.複製表結構及其資料

create table table_name_new as select * from table_name_old2.只複製表結構

create table table_name_new as select * from table_name_old where 1=2;3.只複製表資料

如果兩個表結構一樣：

insert into table_name_new select * from table_name_old如果兩個表結構不一樣：

insert into table_name_new(column1,column2...) select column1,column2... from table_name_old4.如何統計兩個表的記錄總數?

select (select count(id) from aa)+(select count(id) from bb) 總數 from dual; --總數那是沒有單引號的，雙引號可以。5.返回大於等於n的最小整數值?

select ceil(n) from dual;6.返回當前月的最後一天?

select last_day(sysdate) from dual;7.如何查詢重覆記錄？

select * from table_name where rowid!=(select max(rowid) from table_name where table_name.col1=d.col1 and table_name.col2=d.col2);8.如何刪除重覆記錄？

delete from table_name where rowid!=(select max(rowid) from table_name d where table_name.col1=d.col1 and table_name.col2=d.col2);9.表

檢視使用者下所有的表

select * from user_tables;

檢視名稱包含log字元的表

select object_name,object_id from user_objects

where instr(object_name,'log')>0;

檢視某錶的建立時間

select object_name,created from user_objects where object_name=upper('&table_name');

檢視某錶的大小

select sum(bytes)/(1024*1024) as "size(m)" from user_segments

where segment_name=upper('&table_name');

檢視放在oracle的記憶體區里的表

select table_name,cache from user_tables where instr(cache,'y')>0;10.序列號

檢視序列號，last_number是當前值

select * from user_sequences;