Query help: query to return column that represents multiple rows

Question

I have a table with a name and location column. The same name can occur multiple times with any arbitrary location, i.e. duplicates are allowed.
I need a query to find all names that occur in both of two separate locations.
For example,
bob usa
bob mexico
dot mexico
dot europe
hal usa
hal europe
sal usa
sal mexico
The query in question, if given the locations usa and mexico, would return bob and sal.
Thanks for any help or advice,
-=beeky

Answer 1

How about this?
SELECT  NAME
FROM    <LOCATIONS_TABLE>
WHERE   LOCATION IN ('usa','mexico')
GROUP BY NAME
HAVING COUNT(DISTINCT LOCATION) >= 2Results:
SQL> WITH person_locations AS
  2  (
  3          SELECT 'bob' AS NAME, 'USA' AS LOCATION FROM DUAL UNION ALL
  4          SELECT 'bob' AS NAME, 'Mexico' AS LOCATION FROM DUAL UNION ALL
  5          SELECT 'dot' AS NAME, 'Mexico' AS LOCATION FROM DUAL UNION ALL
  6          SELECT 'dot' AS NAME, 'Europe' AS LOCATION FROM DUAL UNION ALL
  7          SELECT 'hal' AS NAME, 'USA' AS LOCATION FROM DUAL UNION ALL
  8          SELECT 'hal' AS NAME, 'Europe' AS LOCATION FROM DUAL UNION ALL
  9          SELECT 'sal' AS NAME, 'USA' AS LOCATION FROM DUAL UNION ALL
10          SELECT 'sal' AS NAME, 'Mexico' AS LOCATION FROM DUAL
11  )
12  SELECT  NAME
13  FROM    person_locations
14  WHERE   LOCATION IN ('USA','Mexico')
15  GROUP BY NAME
16  HAVING COUNT(DISTINCT LOCATION) >= 2
17  /
NAM
bob
salHTH!
Edited by: Centinul on Oct 15, 2009 2:25 PM
Added sample results.