从数据库中的列中显示逗号分隔的下拉值 [英] Showing comma separated dropdown values from column in database

问题描述

我已将下拉选择菜单中的多个选项保存到数据库字段中，并用逗号分隔它们.我现在如何在下拉菜单中再次加载它们?它们被保存为:choice1、choice2、choice55...等.目前我的查询加入了两个表，它看起来像这样:

I have saved multiple choices from dropdown select menu into database field and separate them with comma. How can I load now them in dropdown menu again? They are saved as: choice1,choice2,choice55...etc. Currently my query joining two tables and it's look's like this:

$pdo = Database::connect();
$sql="SELECT t1.*, t2.*
    FROM form_fields t1, user_choices t2
    WHERE t1.field_name = t2.field_name
    and group_id=1 and user_id=".$_SESSION['user_id']." 

    echo '<select class="form-control" name="program">';
    foreach ($pdo->query($sql) as $row_program){
            echo '<option value='.$row_program['field_name'].'>'.$row_program['field_name'].'</option>'; 
    }
echo '</select>';

所以我需要显示来自 user_choices t2 列 program 的值.如果列中只有一个值，则此查询会显示结果.但是当有多个用逗号保存的值时显示错误

So I need to display values from user_choices t2 column program. This query showing result if there is only one value in the column. But when there is multiple value saved with comma showing error

PHP Warning:  Invalid argument supplied for foreach()...

推荐答案

使用带逗号的 explode() 以便它为您提供选项数组，然后在下拉列表中设置动态选项值.

Use explode() with comma so its give you array of options and then set dynamic option values in dropdown.

<?php
$pdo = Database::connect();
$sql="SELECT t1.*, t2.*
    FROM form_fields t1, user_choices t2
    WHERE t1.field_name = t2.field_name
    and group_id=1 and user_id=".$_SESSION['user_id']." ";

echo '<select class="form-control" name="program">';
    foreach ($pdo->query($sql) as $row_program){
        $options = $row_program['field_name'];
        $optionsArr = explode(",", $options);   
        foreach ($optionsArr as $row){
            echo '<option value='.$row.'>'.$row.'</option>'; 
        }
    }
echo '</select>';
?>

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