Question

MY_TABLE = Table with 2 columns Number, City.
Desired Output = City and count of unique Number associated to the city. Seattle, Bellevue is part of Combined. Even though there are 4 numbers associated to Seattle, Bellevue the output is 3 as there are only 3 distinct numbers – 123, 456, 786.

  MY_TABLE
Number   City
123  Seattle
456  Bellevue
789  LosAngeles
780  LosAngeles
123  Bellevue
786  Bellevue

Desired Output:

Combined 3
LosAngeles 2

Query so far:

SELECT NUMBER, CITY FROM MY_TABLE WHERE LOOKUP_ID=100 AND CITY IN 
('Seattle', 'Bellevue', 'LosAngeles')
GROUP BY NUMBER, CITY

Would highly appreciate if anyone provides a recommendations around the same.

Answer 1

You could do something like

SELECT (case when city IN ('Seattle', 'Bellevue') 
             then 'Combined'
             else city
          end) city,
       count( distinct number ) 
  FROM my_table
 WHERE lookup_id = 100
   AND city IN ('Seattle', 'Bellevue', 'LosAngeles')
 GROUP BY (case when city IN ('Seattle', 'Bellevue') 
                then 'Combined'
                else city
           end) 

Of course, my guess is that you have some other table that tells you which CITY values need to be combined rather than having a hard-coded CASE statement.