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Avoiding "Invalid Prepared Statement" Error: Common Pitfalls and Solutions When Using mysqli_stmt::next_result

gitbox 2025-09-12 
<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// This article is for demonstration purposes. The following code is unrelated to the main content.</span></span><span>
</span><span><span class="hljs-variable">$mysqli</span></span><span> = </span><span><span class="hljs-keyword">new</span></span><span> </span><span><span class="hljs-title function_ invoke__">mysqli</span></span><span>(</span><span><span class="hljs-string">"localhost"</span></span><span>, </span><span><span class="hljs-string">"user"</span></span><span>, </span><span><span class="hljs-string">"password"</span></span><span>, </span><span><span class="hljs-string">"test"</span></span>);
</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$mysqli</span></span><span>->connect_errno) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Connection failed: "</span></span><span> . </span><span><span class="hljs-variable">$mysqli</span></span><span>->connect_error;
    </span><span><span class="hljs-keyword">exit</span></span><span>();
}
</span><span><span class="hljs-meta">?></span></span><span>
<hr>
<p><h1>Avoiding the "Invalid Prepared Statement" Error: Common Pitfalls and Solutions When Using mysqli_stmt::next_result</h1></p>
<p><p><br>
When using PHP's <code>mysqli

In the code above, the do...while loop ensures that each result set is fully traversed and freed before moving on to the next. This is key to avoiding the error.

4. Additional Tips

  • In complex business scenarios, try to design stored procedures to return a single result set.
  • Enable mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT); during debugging to quickly locate issues.
  • If multiple result sets must be handled, strictly follow the order "read → free → next_result".

Conclusion

The "Invalid prepared statement" error is essentially caused by improper result set management. Understanding how mysqli_stmt::next_result works and properly handling all result sets in the code is the fundamental solution to this issue. Mastering these techniques will not only improve application stability but also reduce hidden bugs in database interactions.

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