(Simple?) SQL Query: Display all customer information for customers with 2+ orders

I’m doing practice exam material for a distance education course. I have the following three relations (simplified here):

salesperson(emp#, name, salary)
order(order#, cust#, emp#, total)
customer(cust#, name, city)

I’m stuck on a pair of SQL queries.

1. Display all customer info for customers with at least 1 order.

SELECT * FROM customer
  INNER JOIN order ON order.cust# = customer.cust#
  GROUP BY cust#;

2. Display all customer info for customers with at least 2 orders.

SELECT cust#, name, city, industry-type FROM customer
  INNER JOIN order ON order.cust# = customer.cust#
  GROUP BY cust#
  HAVING COUNT(cust#) > 2;

I realize these are misguided attempts resulting from a poor understanding of SQL, but I’ve spent a ton of time on W3School’s SQL Query example tool (https://www.w3schools.com/sql/trysql.asp?filename=trysql_select_where) without getting anywhere, and I finally need some "real" help.

>Solution :

You can try to use subquery to get count by cust# then do inner join to make it.

SELECT c.*
FROM (
    SELECT cust# , COUNT(*) cnt
    FROM order 
    GROUP BY cust#
) o INNER JOIN customer c ON c.cust# = o.cust#
WHERE o.cnt > 2