src/Soluble/Normalist/Synthetic/TableSearch.php
public function toArrayColumn($columnKey, $indexKey)
    {
        $select = clone $this->select;
        $select->reset($select::COLUMNS)->columns([$columnKey, $indexKey]);
        return array_column($select->execute()->toArray(), $columnKey, $indexKey);
    }
public function toArrayColumn($columnKey, $indexKey)
    {
        $select = clone $this->select;
        $select->reset($select::COLUMNS)->columns([$columnKey, $indexKey]);
        return array_column($select->execute()->toArray(), $columnKey, $indexKey);
    }
Return an array indexed by $indexKey
useful for comboboxes...

@param string $columnKey
@param string $indexKey
@return array