This is the table that I am working with:

• stock_item
  category, id, inventory, item, price
• sales
  date, employee, id, item
• employees
  first_name, last_name, phone, role, sinnumber
  I making a query that shows all the sales record an details of the Top Salesperson.

This is my code:

SELECT s.date,
       i.item,
       i.price,
       i.category,
       Concat(e.first_name, "", e.last_name) AS TopSalesPerson
FROM   sales s
       JOIN employees e
         ON s.employee = e.id
       JOIN stock_items i
         ON i.id = s.item
GROUP  BY s.employee
HAVING Max(s.employee); 

However, when I try to filter out the top sales person, it gives me this error:

#1055 – Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column ‘mypetstore.s.date’ which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by