Question

Considering the two tables below called Orders and OrderLines, how many rows would be returned by this SQL query? SELECT o.OrderID, ol.OrderLineID FROM Orders AS o LEFT JOIN OrderLines AS ol ON o.OrderID = ol.OrderID ;

Answer 1

Answer:

The query will return four (4) rows

Explanation:

(See attachment below for the table)

The query will return rows where ORDERID is the same on both tables i.e. table ORDERS and ORDERLINES.

The similar rows (on column ORDERID) are 1897 and 87; for table ORDERLINESS and table ORDERS.

But on table ORDERLINESS, there are three rows with 1897 (under ORDERID column).

In total, they have 4 rows in common which are

ORDERID

1897

1897

1897 and

87