Common SQL statements in PHP

Several MySQL statements commonly used in PHP
Display database or table:
Show databases; // you can then use database_name;
Show tables;
Change Table Name:
Alter table table_name rename new_t;
Add column:
Alter table table_name add column C_n column attributes;
Delete column:
Alter table table_name drop column C_n;
Create an index:
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:
Alter table c_table drop index c_n1;
Change column information:
Alter table t_table change C_1 C_1 varchar (200 );
Alter table t_table modify 1 C_1 varchar (200 );
Insert statement:
Insert into table_name (C_1, C_2)
Values ('x1', 1 );
Update statement:
Update table_name set c_1 = 1 where c_2 = 3;
Delete a database or table:
Drop table table_name;
Drop database database_name; // data that can be deleted using mysql_drop_db.