SQL连接2个表并遍历结果

Question

我有这个SQL查询来从2个表中获取数据，并根据匹配的ID将它们联接起来。

SELECT   *
FROM     bar_items 
   LEFT JOIN bar_cats ON
         bar_cats.cat_id = bar_items.categories
ORDER BY bar_items.categories,
         bar_items.item_name ASC

哪个给我这个结果

我现在正尝试在类别中显示这些类别，并以类别名称作为每个类别的标题。

到目前为止，借助旧的Stack溢出帖子，我已经有了这段代码：here

    $data = array(); 
foreach($results_lists as $row){
        $data[$row['cat_name']][$row['item_name']]['item_name'] = $row['item_name'];
        $data[$row['cat_name']][$row['item_price']]['item_price'] = $row['item_price'];
        $data[$row['cat_name']][$row['item_image']]['item_image'] = $row['item_image'];
    } foreach($data as $category => $events){

        echo $category.'<br>';

        foreach($events as $event){
            echo '    <> '.$event['item_name'].'<br>';
            echo '        <> '.$event['item_price'].'<br>';
            echo '        <> '.$event['item_image'].'<br>';
        }

但它不符合我的需要，并且显示如下：（请注意空白的<>行，并在列表的最下方，即使在查询中返回了某些价格，也不会显示某些价格）

Beer and Bitter
<> John Smiths
<> 
<> 
<> 
<> 2.50
<> 
<> 
<> 
<> 1556315986_john-smiths.jpg
<> Sam Smiths
<> 
<> 
<> 
<> 2.15
<> 
<> 
<> 
<> 1556316430_Samuel_Smith_Brewery_logo.png
<> Stones
<> 
<> 
<> 
<> 
<> 1556316361_stones.jpg
<> Tetleys
<> 
<> 
<> 
<> 
<> 1556315794_tetleys.jpg
Lager
<> Bud Light
<> 
<> 
<> 
<> 2.50
<> 
<> 
<> 
<> 1556316641_bud-light.png
<> Carling
<> 
<> 
<> 
<> 
<> 1556316497_carling-white-011.png
<> Fosters
<> 
<> 
<> 
<> 
<> 1556316197_fosters.png
Cider
<> Strongbow
<> 
<> 
<> 
<> 2.50
<> 
<> 
<> 
<> 1556316131_Strongbow-Logo-1.png

编辑： 当我打印数组时，我得到这个：

Array
(
    [Beer and Bitter] => Array
        (
            [John Smiths] => Array
                (
                    [item_name] => John Smiths
                )

            [2.50] => Array
                (
                    [item_price] => 2.50
                )

            [1556315986_john-smiths.jpg] => Array
                (
                    [item_image] => 1556315986_john-smiths.jpg
                )

            [Sam Smiths] => Array
                (
                    [item_name] => Sam Smiths
                )

            [2.15] => Array
                (
                    [item_price] => 2.15
                )

            [1556316430_Samuel_Smith_Brewery_logo.png] => Array
                (
                    [item_image] => 1556316430_Samuel_Smith_Brewery_logo.png
                )

            [Stones] => Array
                (
                    [item_name] => Stones
                )

            [1556316361_stones.jpg] => Array
                (
                    [item_image] => 1556316361_stones.jpg
                )

            [Tetleys] => Array
                (
                    [item_name] => Tetleys
                )

            [1556315794_tetleys.jpg] => Array
                (
                    [item_image] => 1556315794_tetleys.jpg
                )

        )

    [Lager] => Array
        (
            [Bud Light] => Array
                (
                    [item_name] => Bud Light
                )

            [2.50] => Array
                (
                    [item_price] => 2.50
                )

            [1556316641_bud-light.png] => Array
                (
                    [item_image] => 1556316641_bud-light.png
                )

            [Carling] => Array
                (
                    [item_name] => Carling
                )

            [1556316497_carling-white-011.png] => Array
                (
                    [item_image] => 1556316497_carling-white-011.png
                )

            [Fosters] => Array
                (
                    [item_name] => Fosters
                )

            [1556316197_fosters.png] => Array
                (
                    [item_image] => 1556316197_fosters.png
                )

        )

    [Cider] => Array
        (
            [Strongbow] => Array
                (
                    [item_name] => Strongbow
                )

            [2.50] => Array
                (
                    [item_price] => 2.50
                )

            [1556316131_Strongbow-Logo-1.png] => Array
                (
                    [item_image] => 1556316131_Strongbow-Logo-1.png
                )

        )

)

我要去哪里错了？

谢谢。

Answer 1

我认为您正在使生活变得比实际需要的更加复杂。通过结果集的简单传递应该能够产生您希望的输出。

$last_cat = null;

foreach($results_lists as $row){
    if ( $last_cat != $row['cat_name'] ) {
        echo $row['cat_name'] . '<br>';
        $last_cat = $row['cat_name'];
    }
    echo '    <> '.$row['item_name'].'<br>';
    echo '        <> '.$row['item_price'].'<br>';
    echo '        <> '.$row['item_image'].'<br>';
}