MariaDB Delete查询
MariaDB Delete查询
DELETE命令从指定的表中删除行,并返回删除的数量,使用ROW_COUNT() 函数访问删除的数量。WHERE子句指定删除条件,如果没有指定条件,则删除所有行。LIMIT子句控制删除的行数。
在多行的DELETE语句中,它只删除满足条件的行。DELETE语句允许从不同数据库中的表中删除行,但不允许从表中删除行,然后从子查询中的同一表中进行选择。
以下是DELETE的语法:
DELETE FROM table_name [WHERE …]
你可以通过命令提示符或使用PHP脚本执行DELETE命令。
命令提示符
在命令提示符下,只需使用标准命令:
root@host# mysql –u root –p password; Enter password:******* mysql> use PRODUCTS; Database changed mysql> DELETE FROM products_tbl WHERE product_id=133; mysql> SELECT * from products_tbl WHERE ID_number='133'; ERROR 1032 (HY000): Can't find record in 'products_tbl'
PHP执行DELETE
php使用mysql_query() 方法来执行DELETE命令:
<?php $dbhost = 'localhost:3036'; $dbuser = 'root'; $dbpass = 'rootpassword'; $conn = mysql_connect($dbhost, $dbuser, $dbpass); if(! $conn ) { die('Could not connect: ' . mysql_error()); } $sql = 'DELETE FROM products_tbl WHERE product_id = 261'; mysql_select_db('PRODUCTS'); $retval = mysql_query( $sql, $conn ); if(! $retval ) { die('Could not delete data: ' . mysql_error()); } echo "Deleted data successfully\n"; mysql_close($conn); ?>
成功删除数据后,您将看到以下输出:
mysql> Deleted data successfully mysql> SELECT * from products_tbl WHERE ID_number='261'; ERROR 1032 (HY000): Can't find record in 'products_tbl'