SQL Puzzle | The INNER JOIN – Two Rows PUZZLE | SQL Interview Question

This is something really interesting. Here you have to join these two tables and provide the resultated data but the matching rows into Multiple Rows. Please check out the sample input and the expected output.

Sample Input

Table 1 –

Table 2 –

Expected Output

Script – DDL and INSERT Sample Data

--

CREATE TABLE T1N1
(
	 Id INT
	,Vals Varchar(10)
)
GO

INSERT INTO T1N1 VALUES
(1,'Pawan'),
(2,'Sharlee'),
(3,'Harry')
GO

CREATE TABLE T1N2
(
	 Id INT
	,Vals Varchar(10)
)
GO

INSERT INTO T1N2 VALUES
(1,'Kumar'),
(2,'Diwan')
GO

SELECT * FROM T1N1
GO
SELECT * FROM T1N2
GO


--

SOLUTION 1

--

SELECT Id,Vals
FROM 
(
	SELECT a.* , 1 Ord
	FROM T1N1 a INNER JOIN T1N2 b ON a.Id = b.Id
	UNION ALL
	SELECT b.* , 2 Ord
	FROM T1N1 a INNER JOIN T1N2 b ON a.Id = b.Id
)x
ORDER BY Id, Ord
GO

--

OUTPUT – 1

--

Id          Vals
----------- ----------
1           Pawan
1           Kumar
2           Sharlee
2           Diwan

(4 rows affected)

--

SOLUTION 2

--

SELECT Id,Vals
FROM 
(
	SELECT a.* , 1 Ord
	FROM T1N1 a CROSS APPLY ( SELECT NULL v FROM T1N2 b WHERE a.Id = b.Id )x
	UNION ALL
	SELECT x.* , 2 Ord
	FROM T1N1 a CROSS APPLY ( SELECT * FROM T1N2 b WHERE a.Id = b.Id )x
)x
ORDER BY Id, Ord
GO

--

OUTPUT – 2

--

Id          Vals
----------- ----------
1           Pawan
1           Kumar
2           Sharlee
2           Diwan

(4 rows affected)


--

Enjoy 🙂

Please add comment(s) if you have one or multiple solutions in mind. Thank You.

Pawan Khowal

Pawan is a SQL Server Developer. If you need any help in writing code/puzzle or training please email at – pawankkmr”AT”gmail.com. Meanwhile please go throgh the top pages from his blog.

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