与SQL的数组比较

Question

I want the code below to compare SQL-information from query with a array, in order to not echo same thing twice even though it appear two times in the SQL.

The problem is that one thing gets echo two times. I use print_r in every loop to see how the array changes, and here is how it does along:

Array ( )

Array ( [0] => my_preset )

Array ( [0] => my_preset [1] => test_preset )

The PHP code:

$parentArray = array();
$sql = "SELECT * FROM wb_values";
$result = mysqli_query($conn, $sql);

while ($row = $result->fetch_assoc()) {
    print_r($parentArray);
    if (!in_array($row['parentID'], $parentArray)) {
        array_push($parentArray, $row['parentID']);

        foreach ($parentArray as $parent) {
            $sqlParent = "SELECT * FROM presets WHERE id='$parent'";
            $resultParent = mysqli_query($conn, $sqlParent);
            while ($row = $resultParent->fetch_assoc()) {

            echo "<div class='section'>
                    <div class='left-mark'></div>
                    <p class='text'> ".$row['preset_name']." </p>
                </div>";

            }

        }

    }
}

Answer 1

The problem is that you have the foreach inside the loop that fills the array, so each time a new preset is added you print also the rest of presets included in the array. Just put the foreach after the loop and it should work fine:

$parentArray = array();
$sql = "SELECT * FROM wb_values";
$result = mysqli_query($conn, $sql);

while ($row = $result->fetch_assoc()) {
    print_r($parentArray);
    if (!in_array($row['parentID'], $parentArray)) {
        array_push($parentArray, $row['parentID']);
    }
}

foreach ($parentArray as $parent) {
    $sqlParent = "SELECT * FROM presets WHERE id='$parent'";
    $resultParent = mysqli_query($conn, $sqlParent);
    while ($row = $resultParent->fetch_assoc()) {
        echo "<div class='section'>
            <div class='left-mark'></div>
            <p class='text'> ".$row['preset_name']." </p>
        </div>";
    }
}