如何将多个SQL查询合并为一个以PHP代码形式输出为JSON？

Question

我目前已建立下表：

 StartTime   EndTime    Performer  Event   Day   Location 
 -----------------------------------------------------
  1:00pm      2:00pm     Test       Test    0     1
 11:00pm     12:00am     Test       Test    0     0
  2:00pm      2:30pm     Test       Test    1     0
 11:00pm     12:00am     Test       Test    2     1

JSON输出如下所示：

{
    "day0": {
        "item1": {
            "StartTime": "1:00pm",
            "EndTime": "2:00pm",
            "Performer": "Test",
            "Event": "Test",
            "Location": 1
        },
        "item2": {
            "StartTime": "11:00pm",
            "EndTime": "12:00am",
            "Performer": "Test",
            "Event": "Test",
            "Location": 0
        }
    },
    "day1": {
        "item1": {
            "StartTime": "2:00pm",
            "EndTime": "2:30pm",
            "Performer": "Test",
            "Event": "Test",
            "Location": 0
        }
    },
    "day2": {
        "item1": {
            "StartTime": "11:00pm",
            "EndTime": "12:00am",
            "Performer": "Test",
            "Event": "Test",
            "Location": 1
        }
    }
}

由于我仍在学习PHP，因此我通过对数据库进行3次查询来编写一些草率的代码，每次选择一天分别为1、2和3时的所有数据。

这是用于获取day = 0的数据的代码示例，该代码在day = 1和day = 2时重复执行：

echo '{ "day0" : {';

$sql = "select * from table WHERE day = 0";
$result = mysqli_query($connection, $sql) or die("Error in Selecting " . mysqli_error($connection));

$jsonData = array();
$rowCount = $result->num_rows;
$index = 1;

while($row =mysqli_fetch_assoc($result))
{
    echo '"item'.$index.'":';
    echo json_encode(array("StartTime" => $row['StartTime'], "EndTime" => $row['EndTime'], "Performer" => $row['Performer'], "Event" => $row['Event'], "Location" => intval($row['Location'])));

    if ($rowCount != $index)
    {
        echo ',';
    }
    ++$index;
}

echo ' }';

// Repeated code for day=1

// Repeated code for day=2

echo ' }';

我觉得这只需要一个查询就可以实现，但是由于我是新手，所以我不确定如何实现它。

我开始做这样的事情：

$sql = "select * from table";

$result = mysqli_query($connection, $sql) or die("Error in Selecting " . mysqli_error($connection));

$jsonData = array();
$numOfRows = $result->num_rows;
$count = 1;
while($row = mysqli_fetch_assoc($result))
{
    $outerIndex = 'day'.$row['day'];

    if ($row['day'] == '1')
    {
        // Do something, not sure
    }

    if ( !isset( $jsonData[$outerIndex] ) )
    {            
        $innerIndex = 'item'.$count.'';


        $jsonData[$outerIndex][$innerIndex] = $row;
    }
    ++$count;
}

echo json_encode($jsonData);

但是，我只是被卡住了，并不十分确定如何进一步处理它。

Answer 1

SQL：

$sql = "SELECT * FROM table ORDER BY Day";

进一步深入代码：

$result_object = [];
$item = 1;
while ($row = $result->fetch_assoc()) {
    if(isset($result_object['day'.$row['Day']]))
    {
        $result_object['day'.$row['Day']]['item'.$item] = $row;
        $item++;
    }
    else
    {
        $result_object['day'.$row['Day']]['item1'] = $row;
        $item = 2;
    }
}

然后可以使用以下命令输出它：

echo json_encode($result_object, JSON_PRETTY_PRINT); //JSON_PRETTTY_PRINT is not necessary... 

您可能不同意我的观点，但我不认为用item0，item等索引项目...或day0，day1 ...是一个好主意。 我个人更喜欢遍历结果是：

while ($row = $result->fetch_assoc()) {
    if(isset($result_object[$row['Day']]))
    {
        $result_object[$row['Day']]->items[] = $row;
    }
    else
    {
        $result_object[$row['Day']] = (object)['day'=>$row['Day'], 'items'=>[$row]];
    }

}

在这种情况下，结果将是对象数组。 即：

[
    {
        "day": "0",
        "items": [
            {
                "StartTime": "07:23:56",
                "EndTime": "17:24:04",
                "Performer": "Performer1",
                "Event": "Event1",
                "Day": "0",
                "Location": "1"
            },
            {
                "StartTime": "09:24:30",
                "EndTime": "01:04:37",
                "Performer": "Performer2",
                "Event": "Event2",
                "Day": "0",
                "Location": "1"
            }
        ]
    },
    {
        "day": "1",
        "items": [
            {
                 "StartTime": "10:25:22",
                 "EndTime": "11:25:29",
                 "Performer": "Performer2",
                 "Event": "Event3",
                 "Day": "1",
                 "Location": "2"
            }
         ]
     },
     {
         "day": "2",
         "items": [
             {
                "StartTime": "12:26:08",
                "EndTime": "13:26:12",
                "Performer": "Performer3",
                "Event": "Event4",
                "Day": "2",
                "Location": "1"
             }
        ]
    }
 ]

原因是：您可以轻松使用各种语言遍历每个值（数组）。