sql 连接查询问题
表 A 表B
id name id name
1 write write 写
2 read read 读
2 write
3 read
如果我想要得到这样的效果
表C
id name1 name2
1 空 write
2 read write
3 read 空
请问该如何实现呢？
[解决办法]

CREATE TABLE Ta(ID VARCHAR2(10),NAME VARCHAR2(20));

INSERT INTO TA VALUES('1','write');
INSERT INTO TA VALUES('2','read');
INSERT INTO TA VALUES('2','write');
INSERT INTO TA VALUES('3','read');


SELECT  ID,(SELECT NAME FROM TA WHERE ID=TMP.ID AND NAME='read')NAME1,(SELECT NAME FROM TA WHERE ID=TMP.ID AND NAME='write')NAME2  FROM TA TMP GROUP BY ID;

ID NAME1  NAME2 
1         write 
2  read   write 
3  read