i´m trying to search for orders with one specific article on the order row, but if there more than one row i don´t want to see any of the rows.

This is a sample of two orders where i only want to get one resault. order 9891026 has two rows and 9891025 only have one row.

    select  order_no, line_no
    from customer_order_line
    where order_no in('9891026','9891025')

result

i only want to get

I have don´t have a clue how to make the right query for this.

CodePudding user response：

One way would be to check if an order exists with a line_no greater than 1:

select ol.order_no, ol.line_no
from customer_order_line ol
where ol.order_no in (9891026, 9891025)
and not exists (
  select * from customer_order_line x
  where x.order_no = ol.order_no and x.line_no > 1
);

CodePudding user response：

First find the single-line order numbers order_no (the subquery) and then select from orders with these order numbers only. Please note that a join query (though maybe harder to read) might be more efficient.

select * 
from customer_order_line 
where order_no in
(
 select order_no 
 from customer_order_line
 group by order_no 
 having count(*) = 1
) -- this is the list of single-item orders
and order_no in (9891026,9891025) -- this is the list of target orders

CodePudding user response：

Alternatively, you can do a GROUP BY and use HAVING to make sure only one row is there.

select ol.order_no, min(ol.line_no)
from customer_order_line ol
where ol.order_no in ('9891026', '9891025')
group by ol.order_no
having count(*) = 1