PHP bringing back all rows instead of requested - php

Question

I have a query that is bringing back all rows from the table instead of the fields I have specified. Can you see any mistakes in this? I'm using codeigniter.
Thanks in advance!
unset($conditions);
$conditions['conditions'] = array("accountid"=>$this->sessionInfo['database_account_id'],
"DATE_FORMAT(salestart,'%Y-%m-%d')"=>$today,
"shop"=>"london"
);
$conditions['group_by'] = "item";
$conditions['fields'] = "accountid, item, count(uniqueid) as totalitems, sum(options) as totaloptions, colour";
$today_sales = $this->Database_Model->selectData("sales",$conditions);
My model is:
public function selectData($table,$condition=array()) {
if(isset($condition['fields'])){
$fields = $condition['fields'];
}
else{
$fields = "*";
}
$this->Database->select('*');
$this->Database->from($table);
if(isset($condition['conditions'])){
$this->Database->where($condition['conditions']);
}
if(isset($condition['group_by'])){
$this->Database->group_by($condition['group_by']);
}
if(isset($condition['order_by'])){
$this->Database->order_by($condition['order_by']);
}
if(isset($condition['where_in'])){
$where_in = $condition['where_in'];
foreach($where_in as $key =>$value){
$this->Database->where_in($key,$value);
}
}
if(isset($condition['joins'])){
$joins = $condition['joins'];
foreach($joins as $join){
$this->Database->join($join['table'], $join['joinWith'],$join['type']);
}
}
$query = $this->Database->get();
return $query->result_array();
}

Answer 1

Change this
$this->Database->select('*');
to this
$this->Database->select($fields);