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  • MySql: 常见sql语句

    1. show create table

    mysql> show create table t G
    *************************** 1. row ***************************
    Table: t
    Create Table: CREATE TABLE `t` (
    `a` int(10) unsigned DEFAULT NULL,
    `b` int(10) unsigned DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=latin1
    1 row in set (0.00 sec)

    2. 修改列:  alter table [table_name] change column [original_column_name] [new_column_name] [data_type]:

    mysql> alter table t change column a a int(4) unsigned zerofill;
    Query OK, 0 rows affected (0.14 sec)
    Records: 0 Duplicates: 0 Warnings: 0

         zerofill:  自动填充0到指定宽度,

    mysql> select * from t;
    +------+------+
    | a | b |
    +------+------+
    | 0006 | 2 |
    | 0008 | 5 |
    | 0009 | 4 |
    +------+------+
    3 rows in set (0.00 sec)

    这个只是显示效果,mysql后台存储并不变

    mysql> select a, hex(a) from t;
    +------+--------+
    | a | hex(a) |
    +------+--------+
    | 0006 | 6 |
    | 0008 | 8 |
    | 0009 | 9 |
    +------+--------+
    3 rows in set (0.15 sec)

    3. select @@global.sql_mode, select @@session.sql_mode

    mysql> select @@global.sql_mode;
    +--------------------------------------------+
    | @@global.sql_mode |
    +--------------------------------------------+
    | STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION |
    +--------------------------------------------+
    1 row in set (0.00 sec)

    mysql> select @@session.sql_mode;
    +--------------------------------------------+
    | @@session.sql_mode |
    +--------------------------------------------+
    | STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION |
    +--------------------------------------------+
    1 row in set (0.00 sec)

    mysql>

      

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  • 原文地址:https://www.cnblogs.com/alexyuyu/p/6254547.html
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