Question

I am writing a sql query in Oracle that’s something like this:

 SELECT *
   FROM ( SELECT testid,
                 max(decode(name, 'longitude', stringvalue, NULL)) as longitude,  
                 max(decode(name, 'latitude', stringvalue, NULL)) as latitude
            FROM test_av 
           GROUP  BY testid
        ) av
  INNER JOIN ( 
                  SELECT id,
                          ((ACOS(
                                 SIN(16.15074 * 3.141592653 / 180) 
                                 * SIN(latitude * 3.141592653 / 180) 
                                 + COS(16.15074 * 3.141592653 / 180) 
                                 * COS(latitude * 3.141592653 / 180)
                                 * COS((-22.74426 - longitude)*3.141592653 / 180)
                          )*6373)) as distance
                    FROM test 

        ) t ON t.id = av.testid
  WHERE t.distance <= 100 

When I execute this query Oracle is saying 'longitude invalid identifier'. I was trying to access sub query alias, but the query is failing.

How can I access ‘alias’ of one sub query into another sub query?

Answer 1

If I’m understanding correctly what you’re trying to do, you don’t actually need the INNER JOIN, because you’re not taking any real information from test that’s not already on test_av. So, you can write:

SELECT *
  FROM ( SELECT id,
                longitude,
                latitude,
                ((ACOS( SIN(16.15074 * 3.141592653 / 180)
                        * SIN(latitude * 3.141592653 / 180)
                        + COS(16.15074 * 3.141592653 / 180)
                        * COS(latitude * 3.141592653 / 180)
                        * COS((-22.74426 - longitude) * 3.141592653 / 180)
                )*6373)) AS distance
           FROM ( SELECT testid AS id,
                         max(decode(name, 'longitude', stringvalue, NULL)) as longitude,
                         max(decode(name, 'latitude', stringvalue, NULL)) as latitude
                    FROM test_av
                   GROUP
                      BY testid
                )
       )
 WHERE distance <= 100
;

If you want to explicitly ensure that you only get records that exist in test — that is, if you have records in test_av that don’t have parents in test, and you want to filter those out — then you can handle that in the innermost subquery, after your FROM test_av.