Eloquent get top 5 records from each group-CodePudding

I'm trying to get top 5 records from each category using Eloquent query, similar to sample MySQL query as follows;

SELECT *
FROM (
    SELECT *, ROW_NUMBER() OVER (PARTITION BY secid ORDER BY created_at DESC) AS n
    FROM trees
) AS x
WHERE n <= 5

This is what I tried

  $q= Tree::select(['*',DB::raw("ROW_NUMBER() OVER (PARTITION BY secid ORDER BY created_at DESC) AS n")])
         ->WhereRaw(['n','<=','5'])

->select();

I'm getting "Array to string conversion" error

I tried

->WhereRaw('n','<=','5')

and getting

PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '5 n order by `trees`.`created_at` desc' at line 1

Can anyone please point me what am I doing wrong here? Any help would be highly appreciated.

CodePudding user response：

The first parameter of the whereRow method is an sql string and the second is an array of bindings. To avoid this error you need the following call:

->whereRaw('n <= ?', [5])

But still the query will not build correctly. I suggest you use the following construction:

$subQuery = DB::table('trees')
    ->selectRaw('*, ROW_NUMBER() OVER (PARTITION BY secid ORDER BY created_at DESC) AS n');

$result = DB::query()->fromSub($subQuery, 'x')
    ->where('n', '<=', 5)->whereRaw()
    ->get();