How to do a full outer join of two tables with the same layout not repeating the?

Question

I have to tables with the same layout (same columns). There is one ID and other data. I need a query that returns only one ID setting the data fields to null if that ID wasn't available at the required table.

Example:

Table A 
ID - Val1 - Val2
1 - 2 - 2
2 - 3 - 3
4 - 1 - 5

Table B
ID - Val1 - Val2
2 - 3 - 3
3 - 2 - 1
4 - 2 - 3

Result
ID - Val1A - Val2A - Val1B - Val2B
1 - 2 - 2 - NULL - NULL
2 - 3 - 3 - 3 - 3
3 - NULL - NULL - 2 - 1
4 - 1 - 5 - 2 - 3

I'm using MS SQL Server. Thanks!

I love those downvotes without noone saying anything ..., don't you? — Ignacio Soler Garcia, May 14 '12 at 19:57

score 4 · Accepted Answer · answered May 14 '12 at 19:57

4

use coalesce to grab the non null id, the other columns will be null for the non matching table

select coalesce(a.id,b.id) as ID, Val1A , Val2A , Val1B , Val2B
from TableA a
Full outer join tableB b
ON <.....>

answered May 14 '12 at 19:57

SQLMenace

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score 3 · Answer 2 · answered May 14 '12 at 20:08

SELECT COALESCE(a.ID,b.ID) AS ID, 
      a.Val1 AS TableA_Val1, 
      a.Val2 AS TableA_Val2, 
      b.Val1 AS TableB_Val1,
      b.Val2 AS TableB_Val2
FROM TableA a
FULL OUTER JOIN TableB b
ON a.ID = b.ID

You can test it here: http://sqlfiddle.com/#!3/51b8c/3

How to do a full outer join of two tables with the same layout not repeating the?

2 Answers2