Foreach PHP不起作用

Question

I am trying to execute this code but I get "Invalid argument supplied for foreach()". I can't understand why.

    $team = array(); //The team array consist all the teams that have occured so far in the loop and is empty from the beginning
    if (mysql_num_rows($select_projects) > 0) {

    while($ROW = mysql_fetch_array($select_projects)) {

        //If there is a team assigned to the object that have not occurred before, 
        //create a tr with the teamname as id, 
        //otherwise create a tr with id No team.
        if($ROW['Team'] !== "" && (in_array($ROW['Team'], $team) == False)){  
            echo '<tr id="'.$ROW['Team'].'"> <td>'.$ROW['Team'].'</td>';

                foreach($ROW['PlannedSprint'] as $plannedsprint){

                    if ($plannedsprint == "541"){
                    echo '<td>'.$ROW[DatabaseID].'';
                    }
                }
            echo '</td></tr>';
            array_push($team, $ROW['Team']);
        }
        else if($ROW['Team'] == "" && (in_array($ROW['Team'], $team) == False)){ 
            echo '<tr id="no_team"> <td>No team</td></tr>';
            array_push($team, $ROW['Team']);
        }

    }
}

Answer 1

You should think a little bit of your Database design. I guess you're trying to achieve a one-to-many-relationship between the teams and their planned sprints. Consider the following tables:

Teams:
------------
|ID|Name    |...
|1 |teamOne |...
|2 |teamTwo |...


Sprints:
------------
|ID|Name|byTeam|...
|1 |foo |1     |...
|2 |bar |2     |...
|3 |baz |2     |...
|4 |toDo|NULL  |...

This is the correct way to do this, because a) only the necessary Information will be stored (if a team did 42 sessions, it's not useful to store the teams' name 42 times!) b) it avoids update-anomalies. (if you change the name of a team, you would need to change every sprint-row in your current model) c) you can easily add/remove columns

With this database, your code could be: (using a nice PDO-Feature:)

$db = new PDO('mysql:host=localhost;dbname=workplan', 'mysqlUser', 'mysqlPassw');
$mainQuery = $db->query('SELECT COALESCE(Team.Name,\'No Team\') as teamName, Sprints.Name as taskName, Sprints.ID as taskID FROM Sprints LEFT JOIN Teams ON Sprints.byTeam = Teams.ID ORDER BY Teams.ID');
$resultToShow = $mainQuery->fetchAll(PDO::FETCH_ASSOC|PDO::FETCH_GROUP);
/*fetch_group will combine all rows with the same value for the _first column_ in an associative array. Therefore, the array will now look the following:
Array(
['No Team']=>   Array(
                    Array(
                        ['taskName']=> 'ToDo',
                        ['taskID']=> 4
                    ),
                ),
['teamOne']=>   Array(
                    Array(
                        ['taskName']=>'foo',
                        ['taskId']=>1
                    )
                ),
['teamTwo']=>   Array(
                    Array(
                        ['taskName']=>'Bar',
                        ['taskId']=>2
                    ),
                Array(
                        ['taskName']=>'Baz',
                        ['taskId']=>3
                    )
                )
)
*/
foreach($resultToShow as $teamName => $sprints) {
    /*if you really want to show every sprint as a _column_, use the following lines:
    echo '<tr id=' . $teamName . '><td>' . $teamName . '</td>';        
    foreach($sprints as $sprint){
        echo '<td>'.$sprint['taskID'].'</td>';
    }
    echo '</tr>';
    */
    //But i think you more want a grouped table, so you could use:
    echo '<tr class=' . $teamName . '><td colspan=2>' . $teamName . '</td>';
    foreach($sprints as $sprint){
        echo '<tr><td>'.$sprint['taskID'].'</td><td>'.$sprint['taskName'].'</td></tr>';
    }
}

I really hope this helps you, please don't hesitate to ask if not. I'd recommend you to read a little bit about entity-relationship-models, relationships and SQL joins. They will help you in the future to understand databases and design complex and high-quality Database-Applications :-)