整理Mysql 语句
查看mysql支持的存储引擎: show engines;查看当前默认的存储引擎:
show variables like '%storage_engine%';
查看库中所有表使用的存储引擎
Show table status from db_name;
查看库中指定表的存储引擎
show table status like ‘tb_name‘;
show create table tb_name;
设置表的存储引擎:
ALTER TABLE tb_name ENGINE=InnoDB;
****SQL语句分类:****
******DDL: Data Defination Language******
********CREATE, DROP,> 查看数据库列表:
SHOW DATABASES;
查看库中所有表状态:SHOW TABLE STATUS FROM db_name
创建数据表
CREATE TABLE ‘tbl_name’ (col1 type1修饰符, col2 type2 修饰符, ...)
ALTER TABLE 'tbl_name'字段:
添加字段:add
ADD col1 data_type 删除字段:drop 修改字段:
alter(默认值), change(字段名), modify(字段属性) 索引: 添加索引:add index 删除索引: drop index 表选项
修改:
查看表上的索引:SHOW INDEXES FROM tbl_name;
查看表上的索引:SHOW INDEXES FROM tbl_name;
示例:
创建表
CREATE TABLE students (id int UNSIGNED NOTNULL PRIMARY KEY,name VARCHAR(20)NOTNULL,age tinyint UNSIGNED);
修改表
ALTER TABLE s1 ADD phone varchar(11) AFTERname;
******DML: Data Manipulation Language******
INSERT, DELETE, UPDATE
UPDATE table_reference
SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
注意:一定要有限制条件,否则将修改所有行的指定字段
限制条件: WHERE
LIMIT
示例:
向表插入语句:
INSERT INTO students(id,name) VALUES(3,'jack'),(4,'allen');
SELECT * FROM students ORDER BY name DESC LIMIT 1,2;
******DCL:Data Control Language******
GRANT, REVOKE
GRANT priv_type [(column_list)],... ON priv_level TO 'user'@'host' ;
回收授权:REVOKE priv_type [(column_list)] [, priv_type [(column_list)]] ... ON priv_level FROM user [, user] ...
示例:
授予权限:
GRANT SELECT (col1), INSERT (col1,col2) ON mydb.mytbl TO 'someuser'@'somehost';
回收权限:
REVOKE DELETE ON testdb.* FROM 'testuser'@'%‘
******DQL:Data Query Language******
SELECT
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