Question

How would I write an Zend DB query to select all from the column ID?

So far I have tried:

public function getLatestUserID()
    {
        $ids = $this->select()
             ->where('id = ?');
        return $ids;
    }

But to no avail.

Answer 1

You just want the id column,
You failed to call an execute command.

try:

//assuming you are using a DbTable model
public function getLatestUserID()
    {
        $ids = $this->fetchAll('id');
        return $ids;
    }

I would do it like this, because I use the select() object for everything:

public function getLatestUserID()
    {
        $select = $this->select();
        //I'm not sure if $this will work in this contex but you can out the table name
        $select->from(array($this), array('id'));
        $ids = $this->fetchAll($select);
        return $ids;
    }

The first two examples should return just the id column of the table, now if you actually want to query for a specific id:

 public function getLatestUserID($id)
        {
            $select = $this->select();
            $select->where('id = ?', $id);
            //fetchAll() would still work here if we wanted multiple rows returned
            //but fetchRow() for one row and fetchRowset() for multiple rows are probably
            //more specific for this purpose.
            $ids = $this->fetchRow($select);
            return $ids;
        }