为什么我的PDO $ stmt-> bind_result（）函数调用在执行SELECT查询后挂起？

I have a MySQL database with table "Test" that has one column "TestData". There are three records with the following values for TestData: "This is value 1", "Here is another string", and "Third just for luck".

I wrote the following PHP code to retrieve the records.

<?php

try {
    $hostname = "redacted";
    $username = "redacted";
    $password = "redacted";
    $database = "redacted";

    $conn = new PDO("mysql: host=$hostname; dbname=$database", $username, $password);

    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $sql = "SELECT TestData FROM Test";

    $stmt = $conn->prepare($sql);

    $stmt->execute();
}
catch(PDOException $e)
{
    $finalResult = $finalResult . "," . $e->getMessage();
}

echo "you are here (" . $stmt->rowCount() . ")<br>";

if ($stmt->rowCount() > 0) {

    echo "found (" . $stmt->rowCount() . ")<br>";

    $stmt->bind_result($td);

    echo "bind successful<br>";

    while ($stmt->fetch()) {
        echo "testdata (" . $td . ")<br>";
    }
} else {
    echo "nothing found<br>";
}

?>

The result I receive is

you are here (3)

found (3)

The PHP script never gets to the "echo 'bind successful
'" statement. The "$stmt->bind_result($td);" statement hangs.

The query appears to work, given that rowCount = 3. I've used essentially the same structure to perform INSERTS that work properly.

What's wrong with what I'm doing? Thanks.

I changed my code to the following and it works.

<?php

    $hostname = "redacted";
    $username = "redacted";
    $password = "redacted";
    $database = "redacted";

    $conn = new mysqli($hostname, $username, $password, $database);
    if ($conn->connect_error) {
        fwrite(STDERR, "Connection failed: " . $conn->connect_error . "
");
        exit(1);
    }

    $sql = "SELECT TestData FROM Test WHERE ?";

    $stmt = $conn->stmt_init();

    if(!$stmt->prepare($sql)) {
        print "Failed to prepare statement
";
    } else {
        $stmt->bind_param("s", $condition);
    }

    $condition = "1 = 1";

    $stmt->execute();
    $result = $stmt->get_result();
    while ($row = $result->fetch_array(MYSQLI_NUM)) {
        foreach ($row as $r) {    
            echo "testdata(" . $r . ")<br>";
        }
    }
?>

No more mixing PDO and MySQLi for me. Thanks for the help. Sorry for the inconvenience.

If you are just trying to get the items from the database using php pdo you need to store the results.

$results = $stmt->fetch(); //will get one row

$results = $stmt->fetchAll(); //will take all results and store in an array

hope this helps.