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  • MySQL学习总结之路(第二章:表)

    目录

    MySQL学习总结之路(第一章:服务与数据库管理)

    MySQL学习总结之路(第二章:表)

    MySQL学习总结之路(第三章:数据类型)

    MySQL学习总结之路(第四章:运算符)

    MySQL学习总结之路(第五章:函数)

    MySQL学习总结之路(第六章:表类型【存储引擎】的选择)

    1、创建表

    1.1、创建表基本语法:

    CREATE TABLE tablename (column_name_1 column_type_1 constraints,
    column_name_2 column_type_2 constraints , ……)
    column_name 是列的名字
    column_type 是列的数据类型
    contraints 是这个列的约束条件

    1.1.1、创建一张简单的表

    mysql> create table orders (ordername varchar(10),createtime date,ordermoney decimal(10,2),ordernumber int(2));
    Query OK, 0 rows affected (0.23 sec)

    1.1.2、查看创建表定义

    1.1.2.1、结构化定义

    mysql> desc orders;
    +-------------+---------------+------+-----+---------+-------+
    | Field       | Type          | Null | Key | Default | Extra |
    +-------------+---------------+------+-----+---------+-------+
    | ordername   | varchar(10)   | YES  |     | NULL    |       |
    | createtime  | date          | YES  |     | NULL    |       |
    | ordermoney  | decimal(10,2) | YES  |     | NULL    |       |
    | ordernumber | int(2)        | YES  |     | NULL    |       |
    +-------------+---------------+------+-----+---------+-------+
    4 rows in set (0.00 sec)

    1.1.2.2、表详细定义

    查看详细的表定义

    mysql> show create table orders G;
    *************************** 1. row ***************************
           Table: orders
    Create Table: CREATE TABLE `orders` (
      `ordername` varchar(10) DEFAULT NULL,
      `createtime` date DEFAULT NULL,
      `ordermoney` decimal(10,2) DEFAULT NULL,
      `ordernumber` int(2) DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=latin1
    1 row in set (0.00 sec)
    
    ERROR:
    No query specified

    由此可以看到表的  ENGINE(存储引擎)是InnoDB 

             CHARSET(字符集)是Latin1

    “G”选项的含义是使得记录能够按照字段竖着排列,对于内容比较长的记录更易于显示。

     

    2、删除表

    命令:

    DROP TABLE tablename

    删除orders:

    mysql> drop table orders
        -> ;
    Query OK, 0 rows affected (0.14 sec)

     

    3、修改表

    3.1、修改表类型命令:

    ALTER TABLE tablename MODIFY [COLUMN] column_definition [FIRST | AFTER col_name]
    例:修改表 orders 的 name 字段定义,将 varchar(10)改为 varchar(20):
    mysql> alter table orders modify ordername varchar(20);
    Query OK, 0 rows affected (0.11 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    mysql> desc orders;
    +-------------+---------------+------+-----+---------+-------+
    | Field       | Type          | Null | Key | Default | Extra |
    +-------------+---------------+------+-----+---------+-------+
    | ordername   | varchar(20)   | YES  |     | NULL    |       |
    | createtime  | date          | YES  |     | NULL    |       |
    | ordermoney  | decimal(10,2) | YES  |     | NULL    |       |
    | ordernumber | int(2)        | YES  |     | NULL    |       |
    +-------------+---------------+------+-----+---------+-------+
    4 rows in set (0.00 sec)

    3.2、字段改名命令:

    ALTER TABLE tablename CHANGE [COLUMN] old_col_name column_definition
    [FIRST|AFTER col_name]

    例:表 orders 上将ordernumber修改为ordernumbers

    mysql> alter table orders change column ordernumber ordernumbers int(4);
    Query OK, 0 rows affected (0.06 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    mysql> desc orders;
    +--------------+---------------+------+-----+---------+-------+
    | Field        | Type          | Null | Key | Default | Extra |
    +--------------+---------------+------+-----+---------+-------+
    | ordername    | varchar(20)   | YES  |     | NULL    |       |
    | createtime   | date          | YES  |     | NULL    |       |
    | ordermoney   | decimal(10,2) | YES  |     | NULL    |       |
    | ordernumbers | int(4)        | YES  |     | NULL    |       |
    +--------------+---------------+------+-----+---------+-------+
    4 rows in set (0.00 sec)

    特别说明:change 和 modify 都可以修改表的定义,不同的是 change 后面需要写两次列名,不方便。但是 change 的优点是可以修改列名称,modify 则不能。

    3.3、增加表字段命令:

    ALTER TABLE tablename ADD [COLUMN] column_definition [FIRST | AFTER col_name]
    例:表 orders 上新增加字段 username,类型为 varchar(3):
    mysql> alter table orders add column username varchar(30);
    Query OK, 0 rows affected (0.39 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    mysql> desc orders;
    +-------------+---------------+------+-----+---------+-------+
    | Field       | Type          | Null | Key | Default | Extra |
    +-------------+---------------+------+-----+---------+-------+
    | ordername   | varchar(20)   | YES  |     | NULL    |       |
    | createtime  | date          | YES  |     | NULL    |       |
    | ordermoney  | decimal(10,2) | YES  |     | NULL    |       |
    | ordernumber | int(2)        | YES  |     | NULL    |       |
    | username    | varchar(30)   | YES  |     | NULL    |       |
    +-------------+---------------+------+-----+---------+-------+
    5 rows in set (0.00 sec)

    3.4、删除表列字段命令

    ALTER TABLE tablename DROP [COLUMN] col_name

    例:表 orders 上删除字段 username:

    mysql> alter table orders drop column username;
    Query OK, 0 rows affected (0.53 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    mysql> desc orders;
    +-------------+---------------+------+-----+---------+-------+
    | Field       | Type          | Null | Key | Default | Extra |
    +-------------+---------------+------+-----+---------+-------+
    | ordername   | varchar(20)   | YES  |     | NULL    |       |
    | createtime  | date          | YES  |     | NULL    |       |
    | ordermoney  | decimal(10,2) | YES  |     | NULL    |       |
    | ordernumber | int(2)        | YES  |     | NULL    |       |
    +-------------+---------------+------+-----+---------+-------+
    4 rows in set (0.00 sec)

    3.5、表改名命令

    ALTER TABLE tablename RENAME [TO] new_tablename

    例:表 orders 名字改为goodsorders

    mysql> alter table orders rename goodsorders;
    Query OK, 0 rows affected (0.16 sec)
    
    mysql> desc orders;
    ERROR 1146 (42S02): Table 'ordermanage.orders' doesn't exist
    mysql> desc goodsorders;
    +--------------+---------------+------+-----+---------+-------+
    | Field        | Type          | Null | Key | Default | Extra |
    +--------------+---------------+------+-----+---------+-------+
    | ordername    | varchar(20)   | YES  |     | NULL    |       |
    | createtime   | date          | YES  |     | NULL    |       |
    | ordermoney   | decimal(10,2) | YES  |     | NULL    |       |
    | ordernumbers | int(4)        | YES  |     | NULL    |       |
    +--------------+---------------+------+-----+---------+-------+
    4 rows in set (0.00 sec)

     

    4、DML 语句

    插入(insert)、查询(select)、更新(update)、删除(delete)

    4.1、插入记录 命令

    INSERT INTO tablename (field1,field2,……fieldn) VALUES(value1,value2,……valuesn);

    例:表 goodsorders 中插入一条记录,ordername 为zhang,createtime为2021-05-12,ordermoney为100.00,ordernumbers为:1

    mysql> insert into goodsorders (ordername,createtime,ordermoney,ordernumbers) values('zhang','2021-05-12',100.00,1);
    Query OK, 1 row affected (0.03 sec)

    也可以省略(field1,field2,……fieldn)这一部分

    mysql> insert into goodsorders  values('zhang1','2021-05-12',1001.00,11);
    Query OK, 1 row affected (0.05 sec)

    4.2、查看插入数据命令

    4.2.1、查询全部

    SELECT * FROM tablename [WHERE CONDITION]

    例:查看goodsorders中所有插入数据

    mysql> select * from goodsorders;
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | zhang     | 2021-05-12 |     100.00 |            1 |
    | zhang1    | 2021-05-12 |    1001.00 |           11 |
    +-----------+------------+------------+--------------+
    2 rows in set (0.00 sec)
    其中“*”表示要将所有的记录都选出来

    4.2.2、查询不重复记录命令关键字

    distinct

    例:查询非goodsorders中非重复创建时间(createtime)的数据

    mysql> select  * from goodsorders;
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | zhang     | 2021-03-11 |      50.00 |            1 |
    | li        | 2020-05-12 |      70.00 |           15 |
    | li        | 2020-03-12 |      70.00 |           15 |
    | li        | 2020-03-11 |      70.00 |           15 |
    | li        | 2021-03-11 |      70.00 |           15 |
    +-----------+------------+------------+--------------+
    5 rows in set (0.00 sec)
    
    mysql> select distinct createtime from goodsorders;
    +------------+
    | createtime |
    +------------+
    | 2021-03-11 |
    | 2020-05-12 |
    | 2020-03-12 |
    | 2020-03-11 |
    +------------+
    4 rows in set (0.00 sec)

    由此可以看到,将重复的一条时间数据2021-03-11去掉了

    4.2.3、多条件查询关键字

    where 后面的条件是一个字段的‘=’比较,还可以使用><>=<=!=等比较运算符;
    多个条件之间还可以使用 orand 等逻辑运算符进行多条件联合查询,

    例:查询非goodsorders中 ordername='li'并且createtime为2020-03-11

    mysql> select * from goodsorders where ordername='li'and createtime ='2020-03-11';
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | li        | 2020-03-11 |      70.00 |           15 |
    +-----------+------------+------------+--------------+
    1 row in set (0.00 sec)

    4.2.4、排序查询命名

    SELECT * FROM tablename [WHERE CONDITION] [ORDER BY field1 [DESC|ASC] , field2 
    [DESC|ASC],……fieldn [DESC|ASC]]

    例:把 goodsorders表中的记录按照创建时间高低进行排序显示

    mysql> select * from goodsorders order by createtime;
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | li        | 2020-03-11 |      70.00 |           15 |
    | li        | 2020-03-12 |      70.00 |           15 |
    | li        | 2020-05-12 |      70.00 |           15 |
    | zhang     | 2021-03-11 |      50.00 |            1 |
    | li        | 2021-03-11 |      70.00 |           15 |
    +-----------+------------+------------+--------------+
    5 rows in set (0.01 sec)

    4.2.5、显示一部分,而不是全部,指令

    SELECT ……[LIMIT offset_start,row_count]
    offset_start 表示记录的起始偏移量
    row_count 表示显示的行数
    例如1:显示 goodsorders表中按照 createtiem 排序后的前 3 条记录:
    mysql> select * from goodsorders order by createtime limit 3;
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | li        | 2020-03-11 |      70.00 |           15 |
    | li        | 2020-03-12 |      70.00 |           15 |
    | li        | 2020-05-12 |      70.00 |           15 |
    +-----------+------------+------------+--------------+
    3 rows in set (0.00 sec)

    例如2:如果要显示 goodsorders表中按照 createtiem 排序后 从第二条记录开始,显示3条数据:

    mysql> select * from goodsorders order by createtime limit 2,3;
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | li        | 2020-05-12 |      70.00 |           15 |
    | zhang     | 2021-03-11 |      50.00 |            1 |
    | li        | 2021-03-11 |      70.00 |           15 |
    +-----------+------------+------------+--------------+
    3 rows in set (0.00 sec)

     4.2.6、统计数据,聚合指令

    SELECT [field1,field2,……fieldn] fun_name 
    FROM tablename
    [WHERE where_contition]
    [GROUP BY field1,field2,……fieldn
    [WITH ROLLUP]]
    [HAVING where_contition]

    参数说明:

    1、fun_name 表示要做的聚合操作,也就是聚合函数,常用的有 sum(求和)、count(*)(记录数)、max(最大值)、min(最小值)

    2、GROUP BY 关键字表示要进行分类聚合的字段,比如要按照部门分类统计员工数量,部门就应该写在 group by 后面。

     3、WITH ROLLUP 是可选语法,表明是否对分类聚合后的结果进行再汇总。
    4、HAVING 关键字表示对分类后的结果再进行条件的过滤。
    注意:having 和 where 的区别在于 having 是对聚合后的结果进行条件的过滤,而 where 是在聚合前就对记录进行过滤,如果逻辑允许,我们尽可能用 where 先过滤记录,这样因为结果集减小,将对聚合的效率大大提高,最后再根据逻辑看是否用 having 进行再过滤。
    例1:查询统计goodsorders表中,记录总数
    mysql> select count(1) from goodsorders;
    +----------+
    | count(1) |
    +----------+
    |        5 |
    +----------+
    1 row in set (0.00 sec)

    例2:在此基础上,按照创建日期(createtime)进行分组统计

    mysql> select createtime,count(1) from goodsorders group by createtime;
    +------------+----------+
    | createtime | count(1) |
    +------------+----------+
    | 2020-03-11 |        1 |
    | 2020-03-12 |        1 |
    | 2020-05-12 |        1 |
    | 2021-03-11 |        2 |
    +------------+----------+
    4 rows in set (0.00 sec)

    例3:在此基础上,既要按照创建日期(cretetime)进行分组统计,又要计算总数

    mysql> select createtime,count(1) from goodsorders group by createtime with rollup;
    +------------+----------+
    | createtime | count(1) |
    +------------+----------+
    | 2020-03-11 |        1 |
    | 2020-03-12 |        1 |
    | 2020-05-12 |        1 |
    | 2021-03-11 |        2 |
    | NULL       |        5 |
    +------------+----------+
    5 rows in set (0.02 sec)

    最有一行,null所展示的数字,就是总数

    例4:按照创建日期(createtime)进行分组统计,并且数量大于1

    mysql> select createtime,count(1) from goodsorders group by createtime having count(1)>1;
    +------------+----------+
    | createtime | count(1) |
    +------------+----------+
    | 2021-03-11 |        2 |
    +------------+----------+
    1 row in set (0.00 sec)

    例5:查询goodsorders表中,订单金额(ordermoney)的总额、最低额、最高额

    mysql> select * from goodsorders;
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | zhang     | 2021-03-11 |      50.00 |            1 |
    | li        | 2020-05-12 |      70.00 |           15 |
    | li        | 2020-03-12 |      70.00 |           15 |
    | li        | 2020-03-11 |      70.00 |           15 |
    | li        | 2021-03-11 |      70.00 |           15 |
    +-----------+------------+------------+--------------+
    5 rows in set (0.00 sec)
    
    mysql> select sum(ordermoney),max(ordermoney),min(ordermoney) from goodsorders;
    +-----------------+-----------------+-----------------+
    | sum(ordermoney) | max(ordermoney) | min(ordermoney) |
    +-----------------+-----------------+-----------------+
    |          330.00 |           70.00 |           50.00 |
    +-----------------+-----------------+-----------------+
    1 row in set (0.02 sec)

    4.2.7、表连接

    1、左连接:包含所有的左边表中的记录甚至是右边表中没有和它匹配的记录;关键指令:left join

    2、右连接:包含所有的右边表中的记录甚至是左边表中没有和它匹配的记录;关联指令:right join

     例1:现在我们又创建一张用户表(member),使用goodorders进行左连接,查询关联的用户表信息

    mysql> select * from member;
    +------+------------+
    | id   | membername |
    +------+------------+
    | 15   | zhang      |
    | 1    | li         |
    | 13   | liss       |
    +------+------------+
    3 rows in set (0.00 sec)
    
    mysql> select * from goodsorders;
    +-----------+------------+------------+--------------+----------+
    | ordername | createtime | ordermoney | ordernumbers | memberid |
    +-----------+------------+------------+--------------+----------+
    | zhang     | 2021-03-11 |      50.00 |            1 | 15       |
    | li        | 2020-05-12 |      70.00 |           15 | 1        |
    | li        | 2020-03-12 |      70.00 |           15 | 1        |
    | li        | 2020-03-11 |      70.00 |           15 | 3        |
    | li        | 2021-03-11 |      70.00 |           15 | 1        |
    +-----------+------------+------------+--------------+----------+
    5 rows in set (0.00 sec)
    
    mysql> select * from goodsorders left join member on goodsorders.memberid = member.id;
    +-----------+------------+------------+--------------+----------+------+------------+
    | ordername | createtime | ordermoney | ordernumbers | memberid | id   | membername |
    +-----------+------------+------------+--------------+----------+------+------------+
    | zhang     | 2021-03-11 |      50.00 |            1 | 15       | 15   | zhang      |
    | li        | 2020-05-12 |      70.00 |           15 | 1        | 1    | li         |
    | li        | 2020-03-12 |      70.00 |           15 | 1        | 1    | li         |
    | li        | 2021-03-11 |      70.00 |           15 | 1        | 1    | li         |
    | li        | 2020-03-11 |      70.00 |           15 | 3        | NULL | NULL       |
    +-----------+------------+------------+--------------+----------+------+------------+
    5 rows in set (0.00 sec)

     例2:member和goodsorders中数据不变,我们再来看一下右连接的查询,以及结果:

    mysql> select * from goodsorders right join member on goodsorders.memberid = member.id;
    +-----------+------------+------------+--------------+----------+------+------------+
    | ordername | createtime | ordermoney | ordernumbers | memberid | id   | membername |
    +-----------+------------+------------+--------------+----------+------+------------+
    | zhang     | 2021-03-11 |      50.00 |            1 | 15       | 15   | zhang      |
    | li        | 2020-05-12 |      70.00 |           15 | 1        | 1    | li         |
    | li        | 2020-03-12 |      70.00 |           15 | 1        | 1    | li         |
    | li        | 2021-03-11 |      70.00 |           15 | 1        | 1    | li         |
    | NULL      | NULL       |       NULL |         NULL | NULL     | 13   | liss       |
    +-----------+------------+------------+--------------+----------+------+------------+
    5 rows in set (0.00 sec)

    这里发生了翻转,变为左侧goodsorders 表中的一条数据为空了

    4.2.8、子查询,相关关键字

    主要包括 innot in=!=existsnot exists

    例:从goodsorders表中查询所有用户在memeber表中的记录

    mysql> select * from member;
    +------+------------+
    | id   | membername |
    +------+------------+
    | 15   | zhang      |
    | 1    | li         |
    | 13   | liss       |
    +------+------------+
    3 rows in set (0.00 sec)
    
    mysql> select * from goodsorders;
    +-----------+------------+------------+--------------+----------+
    | ordername | createtime | ordermoney | ordernumbers | memberid |
    +-----------+------------+------------+--------------+----------+
    | zhang     | 2021-03-11 |      50.00 |            1 | 15       |
    | li        | 2020-05-12 |      70.00 |           15 | 1        |
    | li        | 2020-03-12 |      70.00 |           15 | 1        |
    | li        | 2020-03-11 |      70.00 |           15 | 3        |
    | li        | 2021-03-11 |      70.00 |           15 | 1        |
    +-----------+------------+------------+--------------+----------+
    5 rows in set (0.00 sec)
    
    mysql> select * from goodsorders where memberid in(select id from member);
    +-----------+------------+------------+--------------+----------+
    | ordername | createtime | ordermoney | ordernumbers | memberid |
    +-----------+------------+------------+--------------+----------+
    | zhang     | 2021-03-11 |      50.00 |            1 | 15       |
    | li        | 2020-05-12 |      70.00 |           15 | 1        |
    | li        | 2020-03-12 |      70.00 |           15 | 1        |
    | li        | 2021-03-11 |      70.00 |           15 | 1        |
    +-----------+------------+------------+--------------+----------+
    4 rows in set (0.05 sec)

    4.2.9、记录联合,指令

    SELECT * FROM t1
    UNION|UNION ALL
    SELECT * FROM t2
    ……
    UNION|UNION ALL
    SELECT * FROM tn;
    UNION 和 UNION ALL 的主要区别:
         UNION ALL 是把结果集直接合并在一起,
         UNION 是将UNION ALL 后的结果进行一次 DISTINCT,去除重复记录后的结果。

    例1:将member表和goodsorders表中的用户编号id(memberid)的集合显示出来

    mysql> select memberid from goodsorders union all select id from member;
    +----------+
    | memberid |
    +----------+
    | 15       |
    | 1        |
    | 1        |
    | 3        |
    | 1        |
    | 15       |
    | 1        |
    | 13       |
    +----------+
    8 rows in set (0.00 sec)

    例2:如果希望将上面的结果去掉重复记录后显示

    mysql> select memberid from goodsorders union select id from member;
    +----------+
    | memberid |
    +----------+
    | 15       |
    | 1        |
    | 3        |
    | 13       |
    +----------+
    4 rows in set (0.00 sec)

    4.3、更新记录命令

    UPDATE tablename SET field1=value1,field2.=value2,……fieldn=valuen [WHERE CONDITION]

    例:将表 goodsorders 中ordername为zhang的订单金额(ordermoney)改为50

    mysql> update goodsorders set ordermoney=50.00 where ordername='zhang';
    Query OK, 1 row affected (0.09 sec)
    Rows matched: 1  Changed: 1  Warnings: 0
    
    mysql> select * from goodsorders;
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | zhang     | 2021-05-12 |      50.00 |            1 |
    | zhang1    | 2021-05-12 |    1001.00 |           11 |
    +-----------+------------+------------+--------------+
    2 rows in set (0.00 sec)

    更新时,如遇到错误代码1175:

    Error Code: 1175. You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column. To disable safe mode, toggle the option in Preferences

    解决方法:

    1、先进行状体查询:

    show variables like 'SQL_SAFE_UPDATES';

     2、执行下面的sql,关闭safe-updates模式:

    SET SQL_SAFE_UPDATES = 0;

    或者

    SET SQL_SAFE_UPDATES = false;

    4.4、删除记录命名

    DELETE FROM tablename [WHERE CONDITION]

    例:将表 goodsorders 中ordername为zhang1的记录全部删除

    mysql> delete from goodsorders where ordername = 'zhang1';
    Query OK, 1 row affected (0.06 sec)
    
    mysql> select * from goodsorders;
    +-----------+------------+------------+--------------+
    | ordername | createtime | ordermoney | ordernumbers |
    +-----------+------------+------------+--------------+
    | zhang     | 2021-05-12 |      50.00 |            1 |
    +-----------+------------+------------+--------------+
    1 row in set (0.02 sec)

     

    4.5、初始化表

    例:将表中的所有数据清空

    mysql> select * from varc;
    +------+------+
    | v    | c    |
    +------+------+
    | abc  | abc  |
    +------+------+
    1 row in set (0.03 sec)
    
    mysql> truncate table varc;
    Query OK, 0 rows affected (0.25 sec)
    
    mysql> select * from varc;
    Empty set (0.00 sec)

    5、DCL 语句

    DCL语句主要是为了管理数据库系统中的操作对象权限

    5.1创建数据库用户

    例:创建一个数据库用户 user1,初始密码为123,具有对 ordermanage 数据库中所有表的 SELECT/INSERT 权限:
    mysql> grant select,insert on ordermanage.* to 'user1'@'localhost' identified by '123';
    Query OK, 0 rows affected, 1 warning (0.06 sec)
    
    mysql> exit
    Bye
    
    
    C:Program FilesMySQLMySQL Server 5.7in>mysql -uuser1 -p123
    mysql: [Warning] Using a password on the command line interface can be insecure.
    Welcome to the MySQL monitor.  Commands end with ; or g.
    Your MySQL connection id is 82
    Server version: 5.7.17-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
    
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    
    Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
    
    mysql> show databases;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | ordermanage        |
    +--------------------+
    2 rows in set (0.00 sec)

    在此基础上,将此用户(user1)的insert权限进行收回

    mysql> revoke insert on ordermanage.* from 'user1'@'localhost';
    Query OK, 0 rows affected (0.02 sec)
    
    mysql> exit
    Bye
    
    C:Program FilesMySQLMySQL Server 5.7in>mysql -uuser1 -p123
    mysql: [Warning] Using a password on the command line interface can be insecure.
    Welcome to the MySQL monitor.  Commands end with ; or g.
    Your MySQL connection id is 84
    Server version: 5.7.17-log MySQL Community Server (GPL)
    
    Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
    
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    
    Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
    
    mysql> use ordermanage;
    Database changed
    
    mysql> insert into member values('11','ss');
    ERROR 1142 (42000): INSERT command denied to user 'user1'@'localhost' for table 'member'
    mysql>

    由此可以看出插入权限不足,插入失败

    此章节完事儿嘞

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  • 原文地址:https://www.cnblogs.com/19930521zhang/p/14756371.html
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