The database delete statement delete is used to delete one or more rows of data in a table. The syntax format is "DELETE FROM
[WHERE clause] [ORDER BY clause] [LIMIT clause]"; When you do not use the WHERE clause to define the deletion conditions for the deletion operation, all data will be deleted.
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Delete statement delete
The DELETE statement can delete one or more rows of data in the table.
The syntax format is:
DELETE FROM <表名> [WHERE 子句] [ORDER BY 子句] [LIMIT 子句]Copy after loginThe syntax description is as follows:
: Specify the name of the table to delete data.
ORDER BY clause: Optional. Indicates that when deleting, rows in the table will be deleted in the order specified in the clause.
WHERE clause: Optional. Indicates that the deletion conditions are limited for the deletion operation. If this clause is omitted, it means deleting all rows in the table.
LIMIT clause: Optional. Used to tell the server the maximum number of rows to be deleted before the control command is returned to the client.
Example 1: Delete all data in the table
Delete all data in the tb_courses table
mysql> DELETE FROM tb_students; Query OK, 3 rows affected (0.12 sec) mysql> SELECT * FROM tb_students; Empty set (0.00 sec)Copy after loginExample 2: Delete data in the table based on conditions
In the tb_students table, delete the record with id 4
mysql> DELETE FROM tb_students -> WHERE id=4; Query OK, 1 row affected (0.00 sec) mysql> SELECT * FROM tb_students; +----+-------+---------+------+------+--------+------------+ | id | name | dept_id | age | sex | height | login_date | +----+-------+---------+------+------+--------+------------+ | 1 | Dany | 1 | 25 | F | 160 | 2015-09-10 | | 2 | Green | 3 | 23 | F | 158 | 2016-10-22 | | 3 | Henry | 2 | 23 | M | 185 | 2015-05-31 | | 5 | Jim | 1 | 24 | M | 175 | 2016-01-15 | | 6 | John | 2 | 21 | M | 172 | 2015-11-11 | | 7 | Lily | 6 | 22 | F | 165 | 2016-02-26 | | 8 | Susan | 4 | 23 | F | 170 | 2015-10-01 | +----+-------+---------+------+------+--------+------------+ 4 rows in set (0.00 sec)Copy after loginIt can be seen from the running results that the record with id 4 has been been deleted.
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