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When operating a database using PHP , the next_result() function is a very useful function, especially when executing multiple queries, which can help us get query results one by one. This article will explain in depth the role, syntax and parameters of the next_result() function.
The next_result() function is a function used in the MySQLi extension to handle multiple query results. When multiple queries (for example, multiple SQL statements), PHP's MySQLi extension returns multiple result sets. To get each result set, the next_result() function will move you to the next result set so that you can process each query result in succession.
mysqli_next_result(mysqli $link);
$link : This is a MySQLi connection object, usually a connection created through mysqli_connect() or mysqli_init() . This parameter is required to specify the database connection you are operating on.
Return true if moved to the next result set successfully.
Return false if there are no more result sets, or an error occurs.
When you execute multiple SQL statements in a single MySQLi query, for example:
SELECT * FROM users;
SELECT * FROM products;
In this case, you need to get the results of each query one by one. To do this, you can use next_result() to make sure that each result set is fetched correctly. For example:
<?php
// Create a database connection
$link = mysqli_connect("localhost", "username", "password", "database");
// Perform multiple queries
mysqli_multi_query($link, "SELECT * FROM users; SELECT * FROM products;");
// Process the first query result
$result1 = mysqli_store_result($link);
while ($row = mysqli_fetch_assoc($result1)) {
echo $row['username'] . "<br>";
}
// Move to the next result set
if (mysqli_next_result($link)) {
$result2 = mysqli_store_result($link);
while ($row = mysqli_fetch_assoc($result2)) {
echo $row['product_name'] . "<br>";
}
}
// Close the connection
mysqli_close($link);
?>
In this example, we execute two SQL query statements, which are executed via mysqli_multi_query() . Then, we use mysqli_store_result() to get the first query result and use mysqli_next_result() to get and process the next query result.
When executing multiple SQL queries, the next_result() function ensures that the results of each query can be processed one by one. It can handle multiple query result sets executed by mysqli_multi_query() to avoid errors caused by skipping the result set. Especially when handling multiple queries, next_result() can help you successfully traverse the results of all queries.
Make sure that all query results have been processed before calling mysqli_next_result() . If you miss some data while processing the first query result, next_result() may not succeed.
If there are no more result sets, next_result() returns false . At this time, you can use mysqli_more_results() to check whether there are other result sets.
next_result() is a very important function, especially when you need to process multiple query results. It ensures that you can access query results one by one. By understanding its syntax and parameters, database operations and result processing can be performed more efficiently.
