Best way to get result of prepared MySQL statement with maximum of one row

问题

I usually use this code to read/get the result of an prepared MySQL SELECT:

$sqlname = $conn->prepare("SELECT name FROM test1 WHERE test2 = ?");
$sqlname->bind_param('s',$test);
$sqlname->execute();
$result = $sqlname->get_result();
if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {   
        $testname = $row['name'];
    }
}

But when I know that there will only be one row in the result: Do I have to use a while loop with fetch_assoc anyway or is there a better way?

回答1:

When you know the name of the column that you are returning in the result set, you can bind the result to an output variable -- which makes things a little nicer to work with in my opinion.

if (!$stmt = $conn->prepare("SELECT name FROM test1 WHERE test2 = ?")) {
    echo "Prepare Syntax Error"; // $conn->error
} elseif (!$stmt->bind_param("s", $test) || !$stmt->execute() || !$stmt->bind_result($name)) {
    echo "Statement Error"; // $stmt->error
} else {
    $stmt->fetch();
    var_export($name);  // this will show the value or NULL
}

---

Or if you don't want to bind the result value to a variable:

...
} elseif (!$stmt->bind_param("s", $test) || !$stmt->execute() || !$result = $stmt->get_result()) {
    echo "Statement Error"; // $stmt->error
} elseif (!$row = $result->fetch_row()) {  // No need to use assoc() keys
    echo "empty result";
} else {
    var_export($row[0]);  // access the first column value
}

来源：https://stackoverflow.com/questions/52719594/best-way-to-get-result-of-prepared-mysql-statement-with-maximum-of-one-row