SQL RIGHT JOIN
SQL右联接返回右表行中的所有值。它还包含左表中的匹配值,但如果两个表中都没有匹配,则返回NULL。
右连接的基本语法:
SELECT table1.column1, table2.column2.....
FROM table1
RIGHT JOIN table2
ON table1.column_field = table2.column_field;
让我们以2个表为例,table1是CUSTOMERS表,而table2是ORDERS表。
CUSTOMER TABLE:
ID |
NAME |
AGE |
SALARY |
1 |
ARYAN |
51 |
56000 |
2 |
AROHI |
21 |
25000 |
3 |
VINEET |
24 |
31000 |
4 |
AJEET |
23 |
32000 |
5 |
RAVI |
23 |
42000 |
这是第二个表:
ORDER TABLE:
DATE |
O_ID |
CUSTOMER_ID |
AMOUNT |
20-01-2012 |
001 |
2 |
3000 |
12-02-2012 |
002 |
2 |
2000 |
22-03-2012 |
003 |
3 |
4000 |
11-04-2012 |
004 |
4 |
5000 |
在这里,我们将使用SQL RIGHT JOIN将这两个表连接起来:
SQL> SELECT ID,NAME,AMOUNT,DATE
FROM CUSTOMER
RIGHT JOIN ORDER
ON CUSTOMER.ID = ORDER.CUSTOMER_ID;
ID |
NAME |
AMOUNT |
DATE |
2 |
AROHI |
3000 |
20-01-2012 |
2 |
AROHI |
2000 |
12-02-2012 |
3 |
VINEET |
4000 |
22-03-2012 |
4 |
AJEET |
5000 |
11-04-2012 |