Question

I need a SQL statement, the requirement is: there is a table, which has two columns: ID, Owner_ID; I inserted several records, for example:

ID    Owner_ID
0         0
1         0
2         1
3         1
4         2
5         3
6         3
7         3
8         3
9         0

Now I need a SQL statement, which returns a ID list sorted by the number of rows owned by different user, from largest to smallest. In this example, owner 3 has four rows; owner 0 has three rows, owner 1 has two rows; and owner 2 has one rows. the result should be

ID    Owner_ID
5         3
6         3
7         3
8         3
0         0
1         0
9         0
2         1
3         1
4         2

I think I should use the aggregate function count, does anybody have an idea?

I am using HSQLDB.

Thanks in advance!!

Answer 1

This will work with most SQL DBMS, but shows the count value.

SELECT ID, Owner_ID, Owner_Count
  FROM AnonymousTable AS A
  JOIN (SELECT Owner_ID, COUNT(*) AS Owner_Count
          FROM AnonymousTable
         GROUP BY Owner_ID
       ) AS B ON B.Owner_ID = A.Owner_ID
 ORDER BY Owner_Count DESC, Owner_ID ASC, ID ASC;

This will work with some, but not necessarily all, DBMS; it orders by a column that is not shown in the result list:

SELECT ID, Owner_ID
  FROM AnonymousTable AS A
  JOIN (SELECT Owner_ID, COUNT(*) AS Owner_Count
          FROM AnonymousTable
         GROUP BY Owner_ID
       ) AS B ON B.Owner_ID = A.Owner_ID
 ORDER BY Owner_Count DESC, Owner_ID ASC, ID ASC;