Description
SQL Drop Table command can be performed on existing database. Indexes, tables, and databases can easily be erased/evacuated with the DROP statement. The following are the actions performed by drop command.
- Dropping a section from the table.
- Dropping a table from the database.
Syntax
Alter table drop column;
Table_name => Any accurate table.
Column_name =>The operation that can be performed on a column in the table.
Examples
By viewing the below example, the concept of drop command can be understood easily.
[c]sql> desc student;
+------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| stu_id | int(11) | YES | | NULL | |
| stu_name | varchar(255) | YES | | NULL | |
| stu_result | varchar(255) | YES | | NULL | |
| branch | varchar(255) | YES | | NULL | |
| fee | int(11) | YES | | NULL | |
+------------+--------------+------+-----+---------+-------+
5 rows in set (0.00 sec)
sql> alter table student drop column fee;
Query OK, 0 rows affected (0.53 sec)
Records: 0 Duplicates: 0 Warnings: 0
sql> desc student;
+------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| stu_id | int(11) | YES | | NULL | |
| stu_name | varchar(255) | YES | | NULL | |
| stu_result | varchar(255) | YES | | NULL | |
| branch | varchar(255) | YES | | NULL | |
+------------+--------------+------+-----+---------+-------+
4 rows in set (0.00 sec)[/c]
The above example tells that, how to drop a column_name fee from the table.
Syntax
drop table <table name>;
Examples
By viewing the below example, the concept of SQL Drop Table command can be understood easily.
[c]sql> desc student;
+------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| stu_id | int(11) | YES | | NULL | |
| stu_name | varchar(255) | YES | | NULL | |
| stu_result | varchar(255) | YES | | NULL | |
| branch | varchar(255) | YES | | NULL | |
+------------+--------------+------+-----+---------+-------+
4 rows in set (0.00 sec)
sql>drop table student;
Query OK, 0 rows affected (0.48 sec)
sql> select * from student;
ERROR 1146 (42S02): Table 'employee.student' doesn't exist[/c]
The above example tells that, how to drop all the columns from the table student.
SQL Drop Table is used to drop table from a database. It removes the table from the database schema, there is no way to recover the data after execution of this statement on the table.
Key Points
- SQL Drop Table - SQL Drop Table will drop a column from the table and drop table will drop the entire table.