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How to Resolve the 'Commands out of Sync' Error in MySQLi When Using Nested Queries?
How to Resolve the 'Commands out of Sync' Error in MySQLi When Using Nested Queries?
Error: "Commands out of Sync" while Using MySQLi
Problem:
An attempt to execute multiple MySQLi queries simultaneously triggers the "Commands out of sync" error. The nested queries retrieve hierarchical data.
Cause:
MySQL does not allow executing new queries while rows from an in-progress query remain unfetched.
Solution:
Option 1: Use mysqli_store_result()
$result = mysqli_store_result($db); // Execute subsequent queries
This buffers the rows in the MySQL client, allowing multiple queries to be executed.
Option 2: Use mysqli_result::fetch_all()
$result = mysqli_query($db, $sql); $data = mysqli_fetch_all($result, MYSQLI_ASSOC); // Execute subsequent queries
This returns the entire result set as an array, allowing multiple queries to be executed.
Consideration:
The nested queries indicate hierarchical data storage. Consider alternative data models or using frameworks like CodeIgnitor to handle multiple result sets from stored procedures using mysqli_next_result().
CodeIgnitor Implementation:
// Edit code in system/database/drivers/mysqli/mysqli_driver.php
protected function _execute($sql)
{
$results = $this->conn_id->query($this->_prep_query($sql));
@mysqli_next_result($this->conn_id); // Fix 'command out of sync' error
return $results;
}The above is the detailed content of How to Resolve the 'Commands out of Sync' Error in MySQLi When Using Nested Queries?. For more information, please follow other related articles on the PHP Chinese website!
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