MySql Limit rows but without truncating group of rows

Question

I have the following table

id| name     |price| groupid | category
---------------------------------------
1 | product1 | 14  | grp1    | apparel
2 | product1 | 16  | grp1    | apparel
3 | product1 | 36  | grp1    | apparel
4 | product2 | 97  | grp2    | apparel
5 | product2 | 87  | grp2    | apparel
6 | product2 | 77  | grp2    | apparel
7 | product3 | 3   | grp3    | apparel
8 | product3 | 2   | grp3    | apparel
9 | product3 | 5   | grp3    | apparel

I want to fetch products in this table by category and group them by group id in app layer. This is the simple SELECT query I am using:

SELECT * FROM products
WHERE category = 'apparel'
LIMIT 0,5

The problem now is the query truncates the result and the last item in grp2 (id=6) is not returned (as one would expect).

I want a query the detects that one item of a group is not returned, fetching that item as well and then truncates the remainder of the result. Basically I want to return all items of a group or no items in a group at all.

How can i possibly achieve this ?

EDIT: each group can potentially have anywhere between 1 to 12 items. It is variable.

Answer 1

Here's one way of doing it:

SELECT t1.*
FROM products AS t1
JOIN (
   SELECT DISTINCT groupid
   FROM (
      SELECT groupid 
      FROM products
      WHERE category = 'apparel'
      LIMIT 0,5) AS t
) AS t2 ON t1.groupid = t2.groupid

The query uses a derived table that contains all distinct groupid values that belong to the rows returned when LIMIT is applied.

Demo here