Eloquent get last record groupped by date - php

Question

I have a table prices with where I store more times in a day more values referred to a customer like this:
Table prices:
| id | customer_id | value_1 | value_2 | value_3 | created_at |
-------------------------------------------------------------------------
| 1 | 10 | 12345 | 122 | 10 | 2021-08-11 10:12:40 |
| 2 | 10 | 22222 | 222 | 22 | 2021-08-11 23:56:20 |
| 3 | 12 | 44444 | 444 | 44 | 2021-08-12 08:12:10 |
| 4 | 10 | 55555 | 555 | 55 | 2021-08-13 14:11:20 |
| 5 | 10 | 66666 | 666 | 66 | 2021-08-13 15:15:30 |
| 6 | 10 | 77777 | 777 | 77 | 2021-08-13 16:12:50 |
I have some filters on that table to retrieve only records with date greater than X and/or lower than Y, sort records by value_1 or value_2, etc...
With that filters I have to take only 1 record for each day of a customer specified.
I'm able to get the record with the highest value_1 for example, by using sql function max() and group by date.
// Init query
$query = Price::query();
// Take the greatest value of value1
$query = $query->selectRaw(
'max(value_1) as highest_value_1, ' .
'date(created_at) as date'
);
// If defined, add a greater or equals
if ($from) $query->where("created_at", ">=", $from);
// If defined add a lower or equals
if ($to) $query->where("created_at", "<=", $to);
// Get results for current customer only, grupping by date and ordering it
$query = $query->where('customer_id', $id)->groupBy('date')
->orderBy('date', 'DESC');
// Fetch records
$records = $query->get();
But now I would like to have only the last record for each day of a customer specified.
I need an eloquent/sql solution because the date range to search may be large and the table has a lot of records.
How can I archive that?
Thanks

Answer 1

Not a complete solution (no customer filter nor laravel use), but I would use something like that in pure sql :
SELECT
CONCAT(EXTRACT(YEAR_MONTH FROM created_at),EXTRACT(DAY FROM created_at)) AS day,
MAX(created_at)
FROM mytable
GROUP BY day;
Of course, you may use other function to group by day (like string regexp or substr).