How to calculate the number of checks by conditions in one sql query, if each check occupies several lines (by the number of positions in it)?

Question

SQL

There is a table with columns:
1. check number (the first - several lines with "1", the second - several lines with "2", etc.)
2. the number of the unique position in the check (1.2 for the first check, 1,2,3 for second, etc.)
3. the number of goods for each item from item 2.
It is necessary to calculate the number of checks in one request with the condition of a certain number of goods in them.

Answer 1

group by + having