Question

I have two tables like this,

Table1 :

+-------------+--------+--------+--------+
| contract_id | price1 | price2 | price3 |
+-------------+--------+--------+--------+
|           1 |     23 |     45 |     56 |
|           1 |     22 |     21 |    453 |
|           1 |     45 |    564 |    456 |
|           4 |     22 |     21 |    453 |
|           5 |     45 |    564 |    456 |
+-------------+--------+--------+--------+

and Table2,

+-------------+--------+---------+
| contract_id | owner  | address |
+-------------+--------+---------+
|           1 | Me     | Madras  |
|           1 | father | Chennai |
+-------------+--------+---------+

I want to stitch both the tables together so the result appears like,

+-------------+--------+--------+--------+--------+---------+
| contract_id | price1 | price2 | price3 | owner  | address |
+-------------+--------+--------+--------+--------+---------+
|           1 |     23 |     45 |     56 | Me     | Madras  |
|           1 |     22 |     21 |    453 | father | Chennai |
|           1 |     45 |    564 |    456 | NULL   | NULL    |
|           4 |     22 |     21 |    453 | NULL   | NULL    |
|           5 |     45 |    564 |    456 | NULL   | NULL    |
+-------------+--------+--------+--------+--------+---------+

Currently I’m manually iterating through the second table and updating the corresponding rows in first table to acheive this. Other approach I figured out is to do a outer join and
clean up the duplicate rows. Is there a more better way to acheive the result?

Answer 1

We have to join both table by it’s Row_Number.

Try this:

SELECT a.contract_id, a.price1, a.price2, a.price3, b.owner, b.address
FROM (SELECT contract_id, price1, price2, price3, (@rank := @rank + 1) AS rank
      FROM t1, (SELECT @rank := 0) tmp
     )a
LEFT JOIN 
     (SELECT contract_id, owner, address, (@rank1 := @rank1 + 1) AS rank
      FROM t2, (SELECT @rank1 := 0) tmp
     )b
ON a.rank = b.rank
AND a.contract_id = b.contract_id
ORDER BY a.rank ASC;

See this SQLFiddle