1.创建数据表
语句:create table [if not exists] table_name(
column_name data_type,
......
);
2.查看数据表列表
show tables [from db_name]
[like ‘pattern’ | where expr]
(1)查看当前数据表(已打开的)
(2)查看非当前数据表
3查看数据表的创建命令
4.查看数据表结构show columns from table_name;或desc table_name;
5.外键约束操作
foreign key(子表外键列字段名)references 父表名(参照列)
6.修改数据表语句
alter table table_name 修改操作1(添/删),修改操作2(添/删);
(1)添加单列
alter table table_name add [column] col_name col_definition [first | after col_name ];
字段位置:默认最后、first(最前)、after(col_name后)
(2)添加多列
alter table table_name add [column] (col_name col_definition,...);
(3)删除列
alter table table_name drop [column] col_name;
7.添加主键约束
alter table tbl_name add [constraint[symbol*约束标记*]] primary key[index_type](index_col_name);
8.添加唯一约束
alter table tbl_name add [constraint[symbol]] unique [index | key] [index_name] [index_type] (index_col_name,...);
9.添加外键约束
alter table tbl_name add [constraint[symbol]] foreign key [index_name] (index_col_name,...) reference_definition;
10.添加/删除默认约束
alter table tbl_name alter[column] col_name {set default literal | drop default};
11.删除主键约束
alter table tbl_name drop primary key;
12.删除唯一约束
alter table tbl_name drop {index | key} index_name;
13.删除外键约束
alter table tbl_name drop foreign key fk_symbol;
查看表的创建命令,找到外键约束标记
14.修改列定义
alter table tbl_name modify[column]col_name col_definition [first | after col_name];
15.修改列名称
alter table tbl_name change[column]old_col_name new_col_name col_definition [first | after col_name]
change比modify功能多
16.数据表更名
方法1
alter table tbl_name rename [to | as] new_tbl_name
方法2
rename table tbl_name to new_tbl_name [,tbl_name2 to new_tbl_name2]...
17.连接(join)
(1)update tdb_goods inner join tdb_goods_cates on goods_cate=cate_name
set goods_cate=cate_id;
18.创建数据表同时将查询结果写入到数据表
create table [if not exists] tbl_name
[(create_definition,...)]
select_statement
19.字段名不明确处理
update tdb_goods as g inner join tdb_goods_brands as b on g.brand_name=b.brand_name
set g.brand_name=b.brand_id;
20.多表删除(Join作为筛选条件用于delete)
Delete tbl_name[.*] [,tbl_name[.*]]...
From table_references
[where where_condition]
21.修改存储引擎的方法
(1)通过修改mysql配置文件(my.ini)实现
default-storage-engine=engine_name
(2)通过创建数据表命令实现
create table table_name(
...
...
)engine [=] engine_name;
(3)通过修改数据表命令实现
alter table table_name engine [=] engine_name;