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Steps to execute SQL query in PHP: Connect to the database (mysqli_connect) Execute the query (mysqli_query) Get the query results (mysqli_fetch_assoc)
How to execute a simple query in PHP SQL Query
Executing simple SQL queries in PHP is very easy. First, you need to connect to the database. This can be done through the mysqli_connect()
function, where the four parameters correspond to the database server, username, password and database name. For example:
$db_host = 'localhost'; $db_username = 'root'; $db_password = 'password'; $db_name = 'database_name'; $mysqli = mysqli_connect($db_host, $db_username, $db_password, $db_name);
After establishing a database connection, you can use the mysqli_query()
function to execute SQL queries. This function takes the query string as its first parameter and the connection object as its second parameter. It returns a result object containing the query results, or FALSE
if the query fails. For example:
$query = "SELECT * FROM users"; $result = mysqli_query($mysqli, $query);
The result object can be used to obtain query results. The most commonly used method is mysqli_fetch_assoc()
, which returns the current row in the result object as an associative array. For example:
while ($row = mysqli_fetch_assoc($result)) { echo $row['name'] . '<br>'; }
This loop will print out the name
column for each row in the query results.
Practical case
The following is a sample code to obtain all user records in the database:
You need to remember that users must be authenticated before executing SQL queries Input to prevent SQL injection attacks.
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