Why Am I Getting a 'Commands Out of Sync' Error When Running Multiple MySQL Queries in PHP?

"Command out of sync" error in PHP

When executing multiple MySQL queries using mysqli, you may encounter the "Command out of sync; you cannot run this command now" error. This error occurs because mysqli uses non-buffered queries by default, which means that the results of the first query must be retrieved before subsequent queries are executed.

Error reason

In the provided PHP code, two MySQL queries are being executed:

1. $data = $con->query($countQuery)
2. $rows = getRowsByArticleSearch("test", "Auctions", " ")

This error is most likely triggered when a second query is executed before the results of the first query are retrieved.

Solution

There are two ways to solve this problem:

1. Get the results of the first query

Use the mysqli_fetch_*() method to retrieve the results of the first query before executing the second query. For example:

<code class="language-php">$data = $con->query($countQuery);
$rowcount = $data->num_rows;</code>

2. Buffered query

Use mysqli_stmt::store_result() to enable query buffering. This will cause mysqli to store the results of the first query before executing the second query.

<code class="language-php">$numRecords->store_result();</code>

Other instructions

• The error "near '% ? %'" indicates $countQuery that there is a syntax error in the query. Make sure the query is built correctly.
• If you need to execute multiple queries simultaneously, consider using the mysqli::multi_query() method. This method handles buffering and synchronization automatically.

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