obclient> CREATE TABLE tbl1(col1 INT PRIMARY KEY, col2 INT); Query OK, 0 rows affected obclient> INSERT INTO tbl1 VALUES(1,1),(2,2),(3,3),(4,4); Query OK, 4 rows affected Records: 4 Duplicates: 0 Warnings: 0 obclient> SELECT * FROM tbl1; +---+---+ | COL1 | COL...
obclient> CREATE TABLE tbl1(col1 INT PRIMARY KEY, col2 INT); Query OK, 0 rows affected obclient> INSERT INTO tbl1 VALUES(1,1),(2,2),(3,3),(4,4); Query OK, 4 rows affected Records: 4 Duplicates: 0 Warnings: 0 obclient> SELECT * FROM tbl1; +---+---+ | COL1 | COL...
> create table test_tru select *from t_fund_info; Query OK, 1998067 rows affected (35.21 sec) Records: 1998067 Duplicates: 0 Warnings: 0这个时候我们来查看对应的文件,在MySQL中通用的方式,对于每个表会对应单独的数据文件和配置文件。 我们可以看到存在4个新的文件,大小都是一样的。 -rw-rw--- 1 ...
用户表空间： 当开启innodb_file_per_table=1时，数据表从系统表空间独立出来存储在以table_name.ibd命...
1SELECT句法23SELECT[STRAIGHT_JOIN]4[SQL_SMALL_RESULT][SQL_BIG_RESULT][SQL_BUFFER_RESULT]5[SQL_CACHE | SQL_NO_CACHE][SQL_CALC_FOUND_ROWS][HIGH_PRIORITY]6[DISTINCT | DISTINCTROW | ALL]7select_expression,...8[INTO {OUTFILE | DUMPFILE} 'file_name' export_options]9[FROM table_references10...
设置参数innodb_file_per_table=1时,创建表时会自动创建一个segment,同时分配一个extent,包含32个data page的来存储数据,这样创建的空表默认大小就是96KB,extent使用完之后会申请64个连接页,这样对于一些小表,或者undo segment,可以在开始时申请较少的空间,节省磁盘容量的开销。
> create table test_del select *from t_fund_info; Query OK, 1998067 rows affected (33.82 sec) Records: 1998067 Duplicates: 0 Warnings: 0这个时候我们来看看存在大量数据的情况下,修改存储引擎的情况。 可以看到操作的时间还是有着天壤之别 > alter table test_del engine=innodb; ...
Oracle" for linked server Cannot grant, deny, or revoke permissions to sa, dbo, entity owner, information_schema, sys, or yourself. Cannot insert duplicate key row in object... Cannot insert the value NULL into column 'ID', table Cannot open backup device 'C:\TEMP\Demo.bak'. Operating...
And Oracle puts rowids of the duplicates in the exceptions table! Note that this doesn't remove the failing rows. You still need to do that yourself. But it does find them for you. You can use this information to filter the rows you're deleting: ...
I am trying to find if data (let's say rows) duplicate in Table 1 first and remove them. Then I want to see if Table 2 duplicates any of Table 1's rows and remove them from Table 2. Then I will have both tables as clean as I can make things. I can then export the data for...