The SQL UPDATE Statement
The SQL UPDATE Statement
The UPDATE statement is used to modify the existing records in a table.
UPDATE Syntax
UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;
UPDATE Table
The following SQL statement updates the first customer (CustomerID = 1) with a new contact person and a new city.
Example
UPDATE Customers
SET ContactName = 'Alfred Schmidt', City= 'Frankfurt'
WHERE CustomerID = 1;
UPDATE Multiple Records
It is the WHERE clause that determines how many records will be updated.
The following SQL statement will update the contactname to "Juan" for all records where country is "Mexico":
Example
UPDATE Customers
SET ContactName='Juan'
WHERE Country='Mexico';
Example
UPDATE Customers
SET ContactName='Juan';
Example (MySQLi Object-oriented)
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "UPDATE MyGuests SET lastname='Doe' WHERE id=2";
if ($conn->query($sql) === TRUE) {
echo "Record updated successfully";
} else {
echo "Error updating record: " . $conn->error;
}
$conn->close();
?>
Example (MySQLi Procedural)
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
$sql = "UPDATE MyGuests SET lastname='Doe' WHERE id=2";
if (mysqli_query($conn, $sql)) {
echo "Record updated successfully";
} else {
echo "Error updating record: " . mysqli_error($conn);
}
mysqli_close($conn);
?>
Example (PDO)
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDBPDO";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// set the PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "UPDATE MyGuests SET lastname='Doe' WHERE id=2";
// Prepare statement
$stmt = $conn->prepare($sql);
// execute the query
$stmt->execute();
// echo a message to say the UPDATE succeeded
echo $stmt->rowCount() . " records UPDATED successfully";
} catch(PDOException $e) {
echo $sql . "<br>" . $e->getMessage();
}
$conn = null;
?>
