Question

I have a SQL Server database with three tables: Gang, GangMember, and Neighborhood. These tables are structured like this:

Neighborhood
------------
ID (non-null)
Name (non-null)

Gang
----
ID (non-null)
Name (non-null)
NeighborhoodID (nullable)

GangMember
----------
ID (non-null)
GangID (non-null)
Name (non-null),
Position (nullable)

I need to get all gangs a gang member belongs to (yes they can belong to multiple). If there is a neighborhood, I need to return that as well. I want my result set to be in the form of: gang.name, neighborhood.name, member.position

So far, I’ve gotten here:

SELECT
 g.[Name],
 '' as 'Neighborhood' /* This what I don't know how to do */
 m.[Position]
FROM
  [Gang] g, 
  [GangMember] m
WHERE
  m.[GangID]=g.[ID]

Because a gang may not have a neighborhood, I’m not sure how to complete this query. Can somebody help me out? Thanks!

Answer 1

Try this:

SELECT
  g.[Name],
  n.[Name] as 'Neighborhood',
  m.[Position]
FROM 
  [Gang] g INNER JOIN [GangMember] m ON m.[GangID]=g.[ID]
  LEFT OUTER JOIN [Neighborhood] n ON g.[NeighborhoodID] = n.[ID]