What is mysqli_stmt::$num_rows? Basic Usage and Practical Scenarios

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<p><h1>What is mysqli_stmt::</span>$num_rows<span>? Basic Usage and Practical Scenarios</h1></p>
<p><p>When working with PHP to interact with a MySQL database, we usually use <code>mysqli

3. Important Considerations

• You must call store_result() to correctly retrieve num_rows.
• num_rows only works for SELECT queries and is ineffective for INSERT, UPDATE, or DELETE statements.
• If the query result is very large, using store_result() will store all data in memory, so memory usage should be considered.

4. Practical Scenarios

Here are some typical scenarios:

1. In pagination, first count the total number of matching rows to calculate the total number of pages.
2. Check whether a query returned any data, such as verifying if a user account exists during login.
3. Before batch processing data, knowing the number of rows helps display progress or handle data in batches.

In summary, mysqli_stmt::$num_rows is a convenient property for getting the row count of a prepared statement’s result. When combined with store_result(), it makes counting data easy and is suitable for pagination, verification, and data processing scenarios.