Unknown column in field list when use raw in Laravel - mysql

Question

I have a working mysql query like this:
SELECT mc.cart_id, mc.mystore_user_id, MIN(ci.created_at) AS created_at
FROM dmspro_mys_cart AS mc
INNER JOIN dmspro_mys_cart_item AS ci
ON ci.cart_id = mc.cart_id
WHERE mc.is_noticed = 0 AND ci.created_at < '2019-10-08 07:08:39'
GROUP BY mc.cart_id
And I converted it to query builder in my Laravel project:
public function getMinCreatedAt($cartTime)
{
$oSelect = $this->select("{$this->table}.cart_id", "{$this->table}.mystore_user_id",\DB::raw('MIN(ci.created_at) AS created_at'))
->join('cart_item AS ci', 'ci.cart_id', '=', "{$this->table}.cart_id")
->where("{$this->table}.is_noticed", '=', 0)
->where('ci.created_at', '<', $cartTime)
->groupBy("{$this->table}.cart_id")
->get();
return $oSelect;
}
But when I run this, I got error:
Column not found: 1054 Unknown column 'ci.created_at' in 'field list'
(SQL: select dmspro_mys_cart.cart_id,
dmspro_mys_cart.mystore_user_id, MIN(ci.created_at) AS created_at
from dmspro_mys_cart inner join dmspro_mys_cart_item as
dmspro_mys_ci on dmspro_mys_ci.cart_id =
dmspro_mys_cart.cart_id where dmspro_mys_cart.is_noticed = 0
and dmspro_mys_ci.created_at < 2019-10-09 15:51:37 group by
dmspro_mys_cart.cart_id)
How I can fix this?
Thank you!
UPDATE: dmspro_mys_ is my prefix

Answer 1

Your error message does not align with your query.
In the error message an alias named "dmspro_mys_ci" is mentioned, but it does not exist in your query.
Can you please double check this?
Basically your are debuggen the wrong query.
Update
As laravel is setup with prefixing database tables, the alias "ci" is also prefixed.
When referencing this alias in a DB::raw() the table/alias will not automatically be prefixed, so you have to do that yourself by changing:
\DB::raw('MIN(ci.created_at) AS created_at')
to:
\DB::raw('MIN(dmspro_mys_ci.created_at) AS created_at')