CREATE TABLE student ( id INT, sn INT comment '学号', name VARCHAR(20) comment '姓名', qq_mail VARCHAR(20) comment 'QQ邮箱' ); 1. 2. 3. 4. 5. 6. 7. 8. 单行数据 + 全列插入 -- 插入两条记录,value_list 数量必须和定义表的列的数量及顺序一致 INSERT INTO student VALUES (100, ...
File-Per-Table Tablespaces 独占表空间，通过变量innodb_file_per_table控制，在MySQL5.6开始，默认是开启的 innodb_file_per_table=ON 开启后，则每张表会开辟一个表空间，这个文件就是数据目录下的 ibd 文件，不同引擎生成的文件不一样。独占表空间存放表的索引和数据，其他数据如回滚（undo）信息，插入缓冲索引...
1、modify、change都可以修改列的属性;一同的是modify只能修改表的数据类型、change比它要牛逼一点它可以在修改数据类型的同时也修改列名。 2、modify 的语法:alter table table_name modify new_colum_defnition。 如:alter table user modify id bigint; 3、change的语法:alter table table_name change old_colum...
1846 (0A000): ALGORITHM=INPLACE is not supported.问题现象在RDS MySQL实例中,使用INPLACE方式扩展VARCHAR字段长度时,提示如下错误:ERROR 1846 (0A000):ALGORITHM=INPLACE is not suppor...
The parameter innodb_large_prefix was introduced in MySQL 5.5, so that users could avoid accidentally creating tables that would be incompatible with the InnoDB Plugin in MySQL 5.1. Now that MySQL 5.1 is not supported any more, it makes no sense to use any other value than innodb_large_prefi...
隐式输入连接MySQL的密码--charset 指定修改的字符集--defaults-file-F,读取配置文件--alter: 结构变更语句,不需要alter table关键字。可以指定多个更改,用逗号分隔。如下场景,需要注意: 不能用RENAME来重命名表。 列不能通过先删除,再添加的方式进行重命名,不会将数据拷贝到新列。
I have a problem when updating the value in my table from front end its working finr for some times and some times its throwing Mysql error like " lock wait time out exceeded " is it possible to change the value of the variable table_lock_wait_timeout ...
2 rows in set (0.02 sec) --- 可以查询double write的使用情况 mysql> SHOW STATUS LIKE 'innodb_dblwr_%'; +---+---+ | Variable_name | Value | +---+---+ | Innodb_dblwr_pages_written | 14615 | 从BP写入到dblwr的page数 | Innodb_dblwr_writes |...
1mysql my_jira_db < /tmp/alterstatements.sql After running the query for all affected tables, verify that the queries below now return no results; 1SELECT*FROMinformation_schema.COLUMNSWHEREtable_schema='<database-name>'ANDcollation_name!='utf8_bin'; ...
Data in user table as follows UserId Name sex --- 111 user1 f 222 user2 f 333 user3 f 444 user4 m 445 user5 m 446 user6 m Now how can i change sex column from 'm' to 'f' and vice versa in single SQl statement. Thanks, MaheshNavigate: Previous Message•...