Several mysql operations commonly used in PHP and phpmysql operations

Several mysql operations commonly used in PHP and phpmysql operations

Display database or table:

Copy codeThe Code is as follows:
Show databases; // you can then use database_name;
Show tables;

Change Table Name:

Copy codeThe Code is as follows:
Alter table table_name rename new_t;

Add column:

Copy codeThe Code is as follows:
Alter table table_name add column c_n column attributes;

Delete column:

Copy codeThe Code is as follows:
Alter table table_name drop column c_n;

Create an index:

Copy codeThe Code is as follows:
Alter table c_table add index (c_n1, c_n2 );
Alter table c_table add unique index_name (c_n );
Alter table c_table add primary key (sid );

Delete An index:

Copy codeThe Code is as follows:
Alter table c_table drop index c_n1;

Change column information:

Copy codeThe Code is as follows:
Alter table t_table change c_1 c_1 varchar (200 );
Alter table t_table modify 1 c_1 varchar (200 );

Insert statement:

Copy codeThe Code is as follows:
Insert into table_name (c_1, c_2)
Values ('x1', 1 );

Update statement:

Copy codeThe Code is as follows:
Update table_name set c_1 = 1 where c_2 = 3;

Delete a database or table:

Copy codeThe Code is as follows:
Drop table table_name;
Drop database database_name; // data that can be deleted using mysql_drop_db.