What is the difference between deleting a column and emptying a column in a MySQL database using PHP?

Deleting a column in a MySQL database using PHP involves permanently removing the column and all its data from the table structure. Emptying a column, on the other hand, involves removing the data within the column but keeping the column itself in the table structure. If you want to completely remove a column, you would use the ALTER TABLE command to drop the column. If you just want to empty the column of data, you would use the UPDATE command to set the column values to NULL or an empty string. 

// Emptying a column in a MySQL database using PHP
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// SQL query to empty a column named 'column_name' in a table named 'table_name'
$sql = "UPDATE table_name SET column_name = NULL";

if ($conn->query($sql) === TRUE) {
    echo "Column emptied successfully";
} else {
    echo "Error emptying column: " . $conn->error;
}

// Close connection
$conn->close();

Keywords

MySQL database PHP delete column empty column

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