SQL Query GROUP BY Issue in Laravel Query Builder - mysql

Question

I wrote the following MySQL query to get inbox messages of a user with each user and also with last message...
select *, `chat_channel` as `channel`, MAX(id) as max_id from `messages`
where (`message_to` = 2 or `message_from` = 2)
and (`delete_one` <> 2 and `delete_two` <> 2)
group by `channel`
order by `max_id` desc limit 40 offset 0
Laravel Method which I use...
public static function getInboxMessages($user_id, $limit = 40, $offset = 0, $search_key = null)
{
return Message::hasSearch($search_key)->select("*", DB::raw("MAX(id) as max_id"))->where(function ($sql) use (
$user_id
) {
$sql->where('message_to', '=', $user_id);
$sql->orWhere('message_from', '=', $user_id);
})->where(function ($sql) use ($user_id) {
$sql->where('delete_one', '<>', $user_id);
$sql->where('delete_two', '<>', $user_id);
})->with([
'sender' => function ($q) {
$q->select('id', 'uid', 'username', 'full_name', 'picture');
}
])->with([
'receiver' => function ($q) {
$q->select('id', 'uid', 'username', 'full_name', 'picture');
}
])->orderBy('max_id', 'DESC')->groupBy('chat_channel')->offset($offset)->limit($limit)->get();
}
However, when I run this query in phpMyAdmin I encounter the following error...
1055 - Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'db.messages.id' which is not
functionally dependent on columns in GROUP BY clause; this is
incompatible with sql_mode=only_full_group_by
When I run Laravel code directly then I don't receive any error but I do get the records ordered by as expected.

Answer 1

Go to phpMyAdmin -> YourDB -> SQL Tab
Use following command :
SET GLOBAL sql_mode = 'ONLY_FULL_GROUP_BY';
this will enable only full group by for your sql.
To revert the above command changes use :
SET GLOBAL sql_mode=(SELECT REPLACE(##sql_mode,'ONLY_FULL_GROUP_BY',''));

Answer 2

it's the STRICT MODE of mysql for aggregation.
take notice that when you group by something and you select another non aggregated field, the value of that field is not correct 100%. aggregated field are those like the fields you are grouping by, count(field), sum(field),...etc
if you are willing to take that risk, go to config\database.php and edit the strict => true to false
'prefix' => '',
'strict' => false,
'engine' => null,
it is not recommended, and you should rework your query with a join on a group by select
select x from table right join (select gb from table group by gb) as grouped on grouped.gb = table.gb
something like this