1/*Two tables: CUSTOMERS table and ORDERS table.
2ORDERS table contains STATUS attribute.*/
3SELECT
4 customers.customerNumber,
5 customerName,
6 orderNumber,
7 status
8FROM
9 customers
10LEFT JOIN orders ON
11 orders.customerNumber = customers.customerNumber;
1SELECT *
2FROM table_1
3RIGHT JOIN table_2
4ON table_1.common_field = table_2.common_field;
1SELECT table1.column1, table2.column2...
2FROM table1
3LEFT JOIN table2
4ON table1.common_field = table2.common_field;
5
1SELECT * FROM
2(SELECT [column] FROM [table]) a
3LEFT JOIN (SELECT [column1], [columnn2] FROM [table]) b
4ON a.column = b.column1
1SELECT * FROM
2(SELECT [UserID] FROM [User]) a
3LEFT JOIN (SELECT [TailUser], [Weight] FROM [Edge] WHERE [HeadUser] = 5043) b
4ON a.UserId = b.TailUser
1-- LEFT OUTER JOIN is equivalent to LEFT JOIN
2-- b.VALUE1 is null when ID not in table2 (idem for c.VALUE1 in table3)
3SELECT a.ID, a.NAME, b.VALUE1, c.VALUE1 FROM table1 a
4 LEFT OUTER JOIN table2 b ON a.ID = b.ID
5 LEFT OUTER JOIN table3 c ON a.ID = c.ID
6WHERE a.ID >= 1000;
7
8-- ⇓ Test it ⇓ (Fiddle source link)