[英]SQL Right Join issue
我的查询进行了Right Join,但结果不正确。
Null
值必须是NAME_2
列与A
相等A
,我无法弄清楚哪里出了问题。
这是查询:
http://sqlfiddle.com/#!6/cd45b/1
对于未来的读者。 表的定义:
CREATE TABLE S1 (TIME_1 DateTIME, INTERVAL_1 INT, NAME_1 varchar(20),INITIAL_VAL int);
CREATE TABLE S2 (TIME_2 DateTIME, INTERVAL_2 INT, NAME_2 varchar(20), FINAL_VAL int);
与问题有关的数据插入:
INSERT INTO S1 values('10.02.2017 00:00',1, 'B',13);
INSERT INTO S1 values('10.02.2017 01:00',2, 'B',14);
INSERT INTO S1 values('10.02.2017 02:00',3, 'B',10);
INSERT INTO S1 values('10.02.2017 03:00',4, 'B',15);
INSERT INTO S1 values('10.02.2017 00:00',1, 'C',42);
INSERT INTO S1 values('10.02.2017 01:00',2, 'C',10);
INSERT INTO S1 values('10.02.2017 02:00',3, 'C',22);
INSERT INTO S1 values('10.02.2017 03:00',4, 'C',18);
INSERT INTO S2 values('10.02.2017 00:00',1, 'A',12);
INSERT INTO S2 values('10.02.2017 01:00',2, 'A',13);
INSERT INTO S2 values('10.02.2017 02:00',3, 'A',9);
INSERT INTO S2 values('10.02.2017 03:00',4, 'A',16);
INSERT INTO S2 values('10.02.2017 00:00',1, 'B',16);
INSERT INTO S2 values('10.02.2017 01:00',2, 'B',22);
INSERT INTO S2 values('10.02.2017 02:00',3, 'B',20);
INSERT INTO S2 values('10.02.2017 03:00',4, 'B',10);
INSERT INTO S2 values('10.02.2017 00:00',1, 'C',42);
INSERT INTO S2 values('10.02.2017 01:00',2, 'C',15);
INSERT INTO S2 values('10.02.2017 02:00',3, 'C',22);
INSERT INTO S2 values('10.02.2017 03:00',4, 'C',19);
来自问题的初始查询:
WITH CTE1
AS
(
SELECT ROW_NUMBER() OVER (ORDER BY NAME_1) AS V1, * FROM S1
)
,CTE2
AS
(
SELECT ROW_NUMBER() OVER (ORDER BY NAME_2) AS V2,* FROM S2
)
SELECT
CTE2.NAME_2,
CTE2.TIME_2,
INTERVAL_2,
CTE1.INITIAL_VAL,
CTE2.FINAL_VAL
FROM CTE1
RIGHT JOIN CTE2
ON CTE1.V1=CTE2.V2
您的右侧ROW_NUMBER
产生的ROW_NUMBER
匹配。 因此,它的NAME_2
值无关紧要: A
,与NAME_1的值不匹配。
它匹配A
从表S1
与B
从表S2
,因为他们都得到同样的ROW_NUMBER
请运行此命令以查看正确加入后的匹配项:
SELECT ROW_NUMBER() OVER (ORDER BY NAME_1) AS V1, * FROM S1;
SELECT ROW_NUMBER() OVER (ORDER BY NAME_2) AS V2,* FROM S2;
编辑:从评论中回答您的问题。 很难知道您到底需要构建什么,但是我认为间隔可能会带来一些有趣的结果:
WITH CTE1
AS
(
SELECT ROW_NUMBER() OVER (ORDER BY NAME_1) AS V1, * FROM S1
)
,CTE2
AS
(
SELECT ROW_NUMBER() OVER (ORDER BY NAME_2) AS V2,* FROM S2
)
SELECT
CTE2.NAME_2,
CTE2.TIME_2,
INTERVAL_2,
CTE1.INITIAL_VAL,
CTE2.FINAL_VAL
FROM CTE1
RIGHT JOIN CTE2
ON CTE1.NAME_1=CTE2.NAME_2 AND CTE1.INTERVAL_1 = CTE2.INTERVAL_2
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