What is the correct order of using mysql_connect, mysql_error, mysql_select_db, and mysql_query functions in PHP?

When working with MySQL in PHP, it is important to follow a specific order when using the mysql_connect, mysql_error, mysql_select_db, and mysql_query functions. First, establish a connection to the MySQL server using mysql_connect, then select the database you want to work with using mysql_select_db. After that, you can execute queries using mysql_query. It is also important to check for errors using mysql_error after each function call to handle any potential issues. 

// Establish connection to MySQL server
$connection = mysql_connect("localhost", "username", "password");

if (!$connection) {
    die("Connection failed: " . mysql_error());
}

// Select the database
$db_selected = mysql_select_db("database_name", $connection);

if (!$db_selected) {
    die("Database selection failed: " . mysql_error());
}

// Execute a query
$result = mysql_query("SELECT * FROM table_name");

if (!$result) {
    die("Query failed: " . mysql_error());
}

// Process the query result
while ($row = mysql_fetch_assoc($result)) {
    echo $row['column_name'] . "<br>";
}

// Close the connection
mysql_close($connection);

Keywords

mysql_connect mysql_error mysql_select_db mysql_query PHP

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