Mysql will have basic syntax at a glance, and mysql basic syntax

Mysql will have basic syntax at a glance, and mysql basic syntax

Create a table

Create table <table Name> (
<Field Name> type (length) not null primary key auto_increment, ** primary key
Name char (20) not null,
Sex int (4) not nullDefault'0', ** default key
Degree double (16, 2)

)

 

Delete table

Drop table <table Name>;

Clear table

Delete from <Table Name>;

 

Insert data

Insert into <Table Name> [(<field name 1> [,... <field name n>])] values (value 1) [, (value n)]

 

Query a table

Select <Field 1, Field 2,...> from <Table Name> where <expression>

Query the first few fields of a table

Select * from MyClass order by id limit 0, 2;

Total query Fields

Select sum ('field name') from Table Name

Query fields in ascending and descending order

In descending order: select * from table name where expression order by field name desc

Ascending order: select * from table name where Putout = true order by time asc

 

Delete table

Delete from table name where expression

 

Modify Table

Update table name set field = new value ,... Where condition

 

Add Table Fields

Alter table name add other field types;

<1 primary key: alter table name add primary key (field name );

<2 unique constraint: alter table name add unique index name (field name );

 

Delete table fields

Alter table Name drop field name