Insert JSON value is failed

[Ruslan Demianovskii]

When i try to insert json value in my table

Amp\Loop::run(function () {

    $db = Amp\Mysql\pool("...");

    yield $db->query("CREATE TABLE IF NOT EXISTS amp_json (a INT(10), b JSON)");

    /** @var \Amp\Mysql\Statement $statement */
    $statement = yield $db->prepare("INSERT INTO amp_json (a, b) VALUES (?, ?)");
    foreach (range(1, 10) as $num) {
        $json = json_encode(['num' => $num]);
        yield $statement->execute([$num, $json]);
    }

    $db->close();
});

I get an error:

Fatal error: Uncaught Amp\Mysql\QueryError: MySQL error (3144): #22032 Cannot create a JSON value from a string with CHARACTER SET 'binary'. Current query was INSERT INTO amp_json (a, b) VALUES (?, ?) in /vendor/amphp/mysql/src/Internal/Processor.php:617

I was able to insert a row with json value only by concatenating, but it's not good solution.

yield $db->execute("INSERT INTO amp_json (a, b) VALUES ($num, '" . json_encode(['num'=>$num]) . "')");

May be you have some ideas about it?

[Bob Weinand]

Does an explicit conversion in your query work? INSERT INTO amp_json (a, b) VALUES (?, CONVERT(? USING utf8mb4))

I could run your reproduce script without problems though - maybe you've messed your encoding up,, were you running the connection as binary? (Default is utf8mb4_general_ci)

[Ruslan Demianovskii]

@bwoebi thanks for the quick reply!

I added to create query SET utf8mb4 COLLATE = utf8mb4_unicode_ci and replace ? to CONVERT(? USING utf8mb4) in insert query.

This code is working good!

Amp\Loop::run(function () {

    $db = Amp\Mysql\pool("...");

    yield $db->query("CREATE TABLE IF NOT EXISTS amp_json (a INT(10), b JSON) CHARACTER SET utf8mb4 COLLATE = utf8mb4_unicode_ci;");

    /** @var \Amp\Mysql\Statement $statement */
    $statement = yield $db->prepare("INSERT INTO amp_json (a, b) VALUES (?, CONVERT(? USING utf8mb4))");
    foreach (range(1, 10) as $num) {
        $json = json_encode(['num' => $num]);
        yield $statement->execute([$num, $json]);
    }

    $db->close();
});