PHP-为什么它不打印变量，尽管它打印文本？

我对这个php有一些问题，因为它没有从DB返回任何东西，所以我意识到它可能没有从$u POST接收变量。所以我试着把它打印出来，结果它什么也没有返回。所以我手动输入了它的值，但它仍然不打印任何内容！虽然它打印文本，但如果脚本中有语法问题，它也不会打印文本（我想）。所以我不知道怎么了

带有表格的HTML部分被打印出来！ 在最后有一个“回声”的任何东西，它也打印！唯一没有打印的是$nome变量

对不起，葡萄牙语文本，但你不必担心它们

    <?php

        //$nome = $_POST['nome'];
        $nome = "renato";  //ive set the value manually for tests

        $pdo = new PDO('mysql:host=myserver;dbname=mydb', 'myuser', 'mypw');


        if ($nome = ""){
            $sql = $pdo->query("SELECT * FROM clientes");
        }
        else{
            $sql = $pdo->query("SELECT * FROM clientes WHERE nome='".$nome."'");
        }

        echo $nome; //prints nothing!
    ?>

    <table border="1px">
        <tr>
            <td>
                <h3>ID</h3>
            </td>
            <td>
                <h3>NOME</h3>
            </td>
            <td>
                <h3>ENDERECO</h3>
            </td>
            <td>
                <h3>BAIRRO</h3>
            </td>
            <td>
                <h3>CIDADE</h3>
            </td>
            <td>
                <h3>FIS_JUR</h3>
            </td>
            <td>
                <h3>RG</h3>
            </td>
            <td>
                <h3>CPF</h3>
            </td>
            <td>
                <h3>TEL</h3>
            </td><td>
                <h3>TEL2</h3>
            </td>
            <td>
                <h3>DATA_NASC</h3>
            </td>       
        </tr>


//this table gets printed!


    <?php

        while($row = $sql->fetch(PDO::FETCH_ASSOC)){
        echo "
        <tr>
            <td> {$row['id']}
            </td>

            <td> {$row['nome']}
            </td>

            <td> {$row['endereco']}
            </td>

            <td> {$row['bairro']}
            </td>

            <td> {$row['cidade']}
            </td>

            <td> {$row['fis_jur']}
            </td>

            <td> {$row['rg']}
            </td>

            <td> {$row['cpf']}
            </td>

            <td> {$row['tel']}
            </td>

            <td> {$row['tel2']}
            </td>

            <td> {$row['data_nasc']}
            </td>
        </tr>";

//this one prints nothing!
        }

        echo $nome; //prints nothing
        echo "anything"; //yes, this one gets printed
        $pdo = null;
        $sql = null;
    ?>
        </table>

替换此行

if ($nome = ""){

与

您正在赋值，而不是比较

`the problem is that single = sign. rather use double == for comparing.`

the batter way checking empty string use

` if ( empty($nome) ){
    $sql = $pdo->query("SELECT * FROM clientes");
}else{
    $sql = $pdo->query("SELECT * FROM clientes WHERE nome='".$nome."'");
}

`the problem is that single = sign. rather use double == for comparing.`

the batter way checking empty string use

` if ( empty($nome) ){
    $sql = $pdo->query("SELECT * FROM clientes");
}else{
    $sql = $pdo->query("SELECT * FROM clientes WHERE nome='".$nome."'");
}