The functions encapsulated in PHP are not used properly and always prompt parameter issues.

The error means that the first parameter of mysqli in my 167 is wrong? Is there something wrong... I don’t quite understand

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The error means that the first parameter of my 167 mysqli is wrong? Is there still a problem... I don’t quite understand

<code class="php">$link=connect2();
var_dump($link);</code>

Check if your link is an instance of mysqli, that is, if it is similar

<code>function connect2(){
    return new mysqli("localhost", "xxx", "xxx", "xxx_db");
}</code>

http://php.net/manual/zh/mysq...