Simple Count Mysql query

Question

receipt_id           order_id
1                       A
2                       B
3                       B
4                       C
5                       C

What is the sql code to show all the records in this table where order_id's count is more than 1?

Answer 1

Try this:

 Select * from table where order_id in (select  distinct order_id
 from table
 group by order_id
 having count(order_id) > 1)

DEMO

Answer 2

You just need an aggregate function with a GROUP BY

select order_id
from yourtable
group by order_id
having count(order_id) > 1

See SQL Fiddle with Demo