这个 删去 查询用于从数据库表中删除记录。 它通常与“Select”语句一起使用,只删除满足特定条件的记录。
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语法: 删除查询的基本语法是——
让我们考虑下表“数据”,有四列“ID”、“第一名称”、“姓氏”和“年龄”。
要从“数据”表中删除ID为201的人的记录,可以使用以下代码。
使用过程方法删除查询:
<? php $ link = mysqli_connect ("localhost", "root", "", "Mydb"); if($link === false){ die("ERROR: Could not connect. " . mysqli_connect_error()); } $ sql = "DELETE FROM Data WHERE ID=201" ; if(mysqli_query($link, $sql)){ echo "Record was deleted successfully."; } else{ echo "ERROR: Could not able to execute $sql. " . mysqli_error($link); } mysqli_close($link); ?> |
输出: 更新后的表格-
Web浏览器上的输出:
使用面向对象的方法删除查询:
<? php $ mysqli = new mysqli("localhost", "root", "", "Mydb"); if($mysqli === false){ die("ERROR: Could not connect. " . $mysqli->connect_error); } $sql = "DELETE FROM Data WHERE ID=201"; if($mysqli->query($sql) === true){ echo "Record was deleted successfully."; } else{ echo "ERROR: Could not able to execute $sql. " . $mysqli->error; } $mysqli->close(); ?> |
输出: 更新后的表格-
Web浏览器上的输出:
使用PDO方法删除查询:
<? php try{ $ pdo = new PDO(" mysql:host = localhost ; dbname = Mydb ", "root", ""); $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); } catch(PDOException $e){ die("ERROR: Could not connect. " . $e->getMessage()); } try{ $sql = "DELETE FROM Data WHERE ID=201"; $pdo->exec($sql); echo "Record was deleted successfully."; } catch(PDOException $e){ die("ERROR: Could not able to execute $sql. " . $e->getMessage()); } unset($pdo); ?> |
输出: 更新后的表格-
Web浏览器上的输出:
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