Why is it recommended to specify the exact columns to select in a SQL query instead of using "SELECT *" in PHP?

Using "SELECT *" in a SQL query can be inefficient and may retrieve unnecessary columns, leading to increased network traffic and slower query execution. It is recommended to specify the exact columns needed in the SELECT statement to improve query performance and reduce the workload on the database server. 

// Specify the exact columns to select in the SQL query instead of using "SELECT *"
$sql = "SELECT column1, column2, column3 FROM table_name";
$result = mysqli_query($connection, $sql);

// Fetch and display the results
while ($row = mysqli_fetch_assoc($result)) {
    echo $row['column1'] . " - " . $row['column2'] . " - " . $row['column3'] . "<br>";
}

Keywords

PHP SQL query SELECT * columns performance

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