Question

I have a table with following fields and data.

id  type value
1   1    1
2   2    1
3   2    2
4   2    3

After running the query I should get result in temp table like below

1,1
1,2
1,3

and if i have multiple value in type 1 then it should do the same

so if the data is

 id  type value
 1   1    1
 2   1    2
 3   2    1
 4   2    2
 5   2    3

I should get result

1,1
1,2
1,3
2,1
2,2
2,3

Appreciate any help on this.

Answer 1

That looks like:

SELECT t1.value, t2.value
  FROM table t1
  JOIN table t2
    ON t1.type = 1
   AND t2.type = 2
;

which can also be written as:

SELECT t1.value, t2.value
  FROM ( SELECT value FROM table WHERE type = 1 ) t1
 CROSS
  JOIN ( SELECT value FROM table WHERE type = 2 ) t2
;

(The former is simpler, but the latter makes clearer that this is semantically a CROSS JOIN, since the join doesn’t actually depend on any relationship between the joined records.)