mysql> select count(*) from sbtest1; +----------+ | count(*) | +----------+ | 10000000 | +----------+ 1 row in set (0.26 sec) mysql> alter table sbtest1 add column test varchar(128),algorithm=copy; Query OK, 10
I am trying to update and/or add rows to a datable, and although the records are changed in the datatable they are not updated in the database. I can update using sql commands, but I would rather update a row directly and then update the database. I had a look at Dan Carr's pos...
--指定InPlace算法添加列,(5.7版本添加列使用该算法)alter table sbtest1 add column cityname1varchar(10),algorithm=inplace;--指定 instant 算法添加列(8.0版本添加列使用该算法) alter table sbtest2 add column cityname2varchar(10),algorithm=instant; 2.3、设置默认值和删除默认值 代码语言:javascript 代码...
(缺点)并不是所有语句都能复制的比如:insert into table1(create_time) values(now()),取的是数据当前时间,不同的数据可能时间不一致,另外像存储过程和触发器也可能存在问题。 基于行复制(ROW) (优点)从MySQL5.1开始支持基于行的复制,最大的好处是可以正确地复制每一行数据。一些语句可以被更加有效地复制,另外就...
ALTERTABLEorders ADDCONSTRAINTfk_customer FOREIGNKEY(customer_id) REFERENCEScustomers(customer_id); 7. 修改表名 ALTER TABLE old_table_name RENAME TO new_table_name; 以下SQL 语句将表名由 employees 修改为 staff: 实例 ALTERTABLEemployees RENAMETOstaff; ...
mysql>show tables;+---+|Tables_in_test|+---+|student_info|+---+1rowinset(0.00sec) mysql> (2)添加列 格式:ALTER TABLE 表名 ADD COLUMN 列名 类型名; mysql>ALTERTABLEstudent_infoADDCOLUMNscoreint; Query OK,15rows affected (0.12sec) Records:15Duplicates:0Warnings...
1 row in set (0.00 sec) mysql> alter table employee rename to users; Query OK, 0 rows affected (0.01 sec) mysql> show tables; +---+ | Tables_in_ForTest | +---+ | users | +---+ 1. 2. 3. 4. 5. 6. 7. 8. 9.
基本语法:CREATETABLE[IF NOT EXISTS][数据库名.]表名ASsubquery;介绍:此方式可以自定义选择子查询中的字段来创建table2后, 子查询中对应字段数据也一并转移至table2中 注意:只是复制数据,而具体的约束是无法复制的创建表举例:CREATETABLEIFNOTEXISTSdbtest.teacherASSELECTtid,tname,tsex,tage,taddressFROMdemo_sc...
metadata only". Therefore, ADD/DROP COLUMN operations aren't dependent on the table size anymore. In other words, the time taken to ADD/DROP new/old column(s) to/from a table with 1 row would be the same as time taken to ADD/DROP new/old column(s) to/from a table having 100M ...
Add to Row Posted by:Julia Fleur Date: March 04, 2010 10:05PM I created a drop down menu for a table called 'students' with an index. How can I apply the same name i selected from table 'students' (in the drop-down menu) to another table called 'data' in a form?