Question

我试图将$ row []值分配给变量，以便我可以在表单中使用它。由于我两次加入表，因此2列具有相同的名称。我试图使用如图所示的别名来分配变量，但它们返回null（可能是语法错误？）。查询检查正常

<?php
//This will list player info so the user can get the correct player  ID
$STH = $db->query('
                SELECT wW.id, wW.dateStart, wW.dateEnd, wW.weekNumber, wW.team1Id, wW.team2Id, wT1.name, wT2.name 
                FROM wdlWeeks wW
                JOIN wdlTeams wT1 on wT1.id = wW.team1Id
                JOIN wdlTeams wT2 on wT2.id = wW.team2Id
            ');

//Setting the fetch mode
$STH->setFetchMode(PDO::FETCH_ASSOC);

//Output all players with their ID's

while($row = $STH->fetch()) {

    $id = $row['wW.id'];
    $team1Name = $row['wT1.name'];
    $team2Name = $row['wT2.name'];
    $dateStart = $row['wW.dateStart'];
    $dateEnd = $row['wW.dateEnd'];
    $weekNumber = $row['wW.weekNumber'];

    echo "<option value='$id'>$team1Name vs. $team2Name (Week: $weekNumber - $dateStart - $dateEnd)</option>";
    echo "<br>";
}

?>

Answer 1

您不需要每个变量前面的wW.等，这些列将仅作为其名称返回

另外，由于您有2个具有相同名称的列，因此您必须修改查询，以便为其中一个name列添加另一个名称

$STH = $db->query('
            SELECT wW.id, wW.dateStart, wW.dateEnd, wW.weekNumber, 
                 wW.team1Id, wW.team2Id, wT1.name, wT2.name as t2name
            FROM wdlWeeks wW
            JOIN wdlTeams wT1 on wT1.id = wW.team1Id
            JOIN wdlTeams wT2 on wT2.id = wW.team2Id
        ');
//Setting the fetch mode
$STH->setFetchMode(PDO::FETCH_ASSOC);

//Output all players with their ID's

while($row = $STH->fetch()) {
    $id = $row['id'];
    $team1Name = $row['name'];
    $team2Name = $row['t2name'];
    $dateStart = $row['dateStart'];
    $dateEnd = $row['dateEnd'];
    $weekNumber = $row['weekNumber'];

    echo "<option value='$id'>$team1Name vs. $team2Name (Week: $weekNumber - $dateStart - $dateEnd)</option>";
    echo "<br>";
}

Answer 2

您可以为每个字段使用别名：

SELECT wW.id，wW.dateStart，wW.dateEnd，wW.weekNumber，wW.team1Id，wW.team2Id， wT1.name AS Team1Name，wT2.name AS Team2Name 来自wdlWeeks wW 在wT1.id = wW.team1Id上加入wdlTeams wT1 在wT2.id = wW.team2Id

上加入wdlTeams wT2

然后：

$ team1Name = $ row ['Team1Name']

Answer 3

别名是默认的列名，因此您使用＆＃39; name＆＃39;有两列，并且根本不包含表别名。例如，在查询中使用AS wT1name，然后将这些字符串用于从$ row中提取的别名。像这样：

<?php
//This will list player info so the user can get the correct player  ID
$STH = $db->query('
                SELECT wW.id, wW.dateStart, wW.dateEnd, wW.weekNumber, wW.team1Id, wW.team2Id, wT1.name AS wT1name, wT2.name AS wT2name
                FROM wdlWeeks wW
                JOIN wdlTeams wT1 on wT1.id = wW.team1Id
                JOIN wdlTeams wT2 on wT2.id = wW.team2Id
            ');

//Setting the fetch mode
$STH->setFetchMode(PDO::FETCH_ASSOC);

//Output all players with their ID's

while($row = $STH->fetch()) {

    $id = $row['id'];
    $team1Name = $row['wT1name'];
    $team2Name = $row['wT2name'];
    $dateStart = $row['dateStart'];
    $dateEnd = $row['dateEnd'];
    $weekNumber = $row['weekNumber'];

    echo "<option value='$id'>$team1Name vs. $team2Name (Week: $weekNumber - $dateStart - $dateEnd)</option>";
    echo "<br>";
}

?>

从两次连接的表中分配变量

3 个答案: