它没有显示aantalkeermenu。 有人知道为什么吗？

My question is why it don't show $aantalkeermenu. but it show's the other variable's from the query can anyone help me with that?

This is my query:

$sql = "SELECT res.reserveringsnr, res.datum, menr.reserveringsnr, menr.menunr, SUM(menr.aantalkeermenu), men.menunr, men.menunaam, men.voorgerecht, men.hoofdgerecht, men.nagerecht  FROM reserveringen AS res
                INNER JOIN menus_regel as menr
                ON res.reserveringsnr = menr.reserveringsnr
                INNER JOIN menus AS men
                ON menr.menunr = men.menunr
                WHERE res.datum = '".$invoerdatum."'
                GROUP BY menr.menunr 
                ";

Here is show it on my webpage:

        $result = mysql_query($sql);

        echo "<table>";
        echo "<th>Aantal</th> <th> Menunaam </th><th> Voorgerecht </th> <th> Hoofdgerecht </th> <th> Nagerecht </th>";

        while($row = mysql_fetch_assoc($result)) {
            $datum = $row['datum'];
            $aantalkeermenu = $row['aantalkeermenu'];
            $menunr = $row['menunr'];
            $menunaam = $row['menunaam'];
            $voorgerecht = $row['voorgerecht'];
            $hoofdgerecht = $row['hoofdgerecht'];
            $nagerecht = $row['nagerecht'];
            $aantalkeermenu = $row['aantalkeermenu'];


        // open tr
        echo "<tr id='$menunr' class='edit_tr'>";
        echo "<td><span>$menunr</span></td>";           
        echo "<td><span>$aantalkeermenu</span></td>"; 
        echo "<td><span>$menunaam</span></td>"; 
        echo "<td><span>$voorgerecht</span></td>"; 
        echo "<td><span>$hoofdgerecht</span></td>"; 
        echo "<td><span>$nagerecht</span></td>"; 



        echo "</tr>"; 
        // close tr
        }           
        echo "</table>";

When you

select ... SUM(menr.aantalkeermenu)

the resulting column won't be called aantalkeermenu. You need to explicitely name the column, like this

select ... SUM(menr.aantalkeermenu) as aantalkeermenu

and then it will appear in under that name in the resulting row.

You need to alias the SUM(menr.aantalkeermenu) other wise I believe it is returned as SUM(menr.aantalkeermenu)

The following SQL should help.

$sql = "
SELECT res.reserveringsnr, res.datum, menr.reserveringsnr, menr.menunr,
SUM(menr.aantalkeermenu) AS aantalkeermenu, men.menunr, men.menunaam, men.voorgerecht,
men.hoofdgerecht, men.nagerecht 
FROM reserveringen AS res
INNER JOIN menus_regel as menr
ON res.reserveringsnr = menr.reserveringsnr
INNER JOIN menus AS men
ON menr.menunr = men.menunr
WHERE res.datum = '".$invoerdatum."'
GROUP BY menr.menunr";