Question

I need to run a query which find a count of different categories. For example:
Let’s say, route No: 10,20,40 are categorized under “Short-routes” and route No: “45,60 and 70” are categorized under “Long-routes”. Different buses ply over one or more of these routes.

Example: (A, B, C are bus Nos)

Bus No. Route

• A 10
• A 45
• B 40
• B 45
• B 60
• A 20
• C 70

I am trying to write a sql query which would return the count of categories each bus ply or does not ply to (indicated by a count of zero for that category):
That is:

• Bus NO. Short Route Long Route
• A 2 1
• B 1 2
• C 0 1

The information that C does not ply (0 count) on a short route is imperative. How can I get my query to return me the result as above?

Thank you!

Answer 1

You could use case statements:

SELECT BusNo, 
    SUM (CASE WHEN Route in (10,20,40) THEN 1 ELSE 0 END)) AS ShortRoute,
    SUM (CASE WHEN Route in (45,60,70) THEN 1 ELSE 0 END)) AS LongRoute
FROM RoutesTable
GROUP BY BusNo

If the long/short route info is contained in another table, let’s say RouteInfo:

SELECT BusNo, 
    SUM (CASE WHEN RouteInfo.Route = 'short' THEN 1 ELSE 0 END)) AS ShortRoute,
    SUM (CASE WHEN RouteInfo.Route = 'long' THEN 1 ELSE 0 END)) AS LongRoute
FROM RoutesTable
    INNER JOIN RouteInfo ON RoutesTable.Route = RouteInfo.Route
GROUP BY BusNo