Question

If I am creating temporary tables, that have 2 columns. id and score. I want to to add them together.

The way I want to add them is if they each contain the same id then I do not want to duplicate the id but instead add the scores together.

if I have 2 temp tables called t1 and t2

and t1 had:

id 3 score 4
id 6 score 7

and t2 had:

id 3 score 5
id 5 score 2

I would end up with a new temp table containing:

id 3 score 9
id 5 score 2
id 6 score 7

The reason I want to do this is, I am trying to build a product search. I have a few algorithms I want to use, 1 using fulltext another not. And I want to use both algorithms so I want to create a temporary table based on algorithm1 and a temp table based on algorithm2. Then combine them.

Answer 1

How about:

SELECT id, SUM(score) AS score FROM (
  SELECT id, score FROM t1
  UNION ALL
  SELECT id, score FROM t2
) t3
GROUP BY id