MySQL Using Group By to get unique values from description field and splitting on separator

Question

Say I have this table of car sales:

DESCRIPTION       AMOUNT
--------------    -------
Ford: Tarus       $10,000
Honda: Accord     $11,000
Honda: Accord     $12,000
Chevy: Equinox    $13,000
Ford: Explorer    $14,000
Ford: Explorer    $15,000
Dodge: Dart       $16,000
Ford: Explorer    $17,000

If I want to see the total money brought in by each unique description I could say:

SELECT description, count(description) AS sales_count, SUM(amount) AS total_amount
FROM car_sales
GROUP BY description
ORDER BY total_amount DESC, sales_count DESC

and get a nice report like this:

DESCRIPTION       SALES_COUNT    TOTAL_AMOUNT
--------------    -----------    ------------
Ford: Explorer    3              $46,000
Honda: Accord     2              $23,000
Dodge: Dart       1              $16,000
Chevy: Equinox    1              $13,000
Ford: Tarus       1              $10,000

Now notice how my description is just the make and model separated by a colon. I can't change the way the description column is formatted but I would like to get a response that shows a breakdown by make and then also by model. Kinda like splitting it on the : colon . How would I write my SQL query to do this and get a table like this?

DESCRIPTION       SALES_COUNT    TOTAL_AMOUNT
--------------    -----------    ------------
Ford              4              $56,000
   Explorer       3              $46,000
   Tarus          1              $10,000
Honda             2              $23,000
   Accord         2              $23,000
Dodge             1              $16,000
   Dart           1              $16,000
Chevy             1              $13,000
   Equinox        1              $13,000

Answer 1

You can do what you want using the with rollup option on group by (supported by both MySQL and SQL Server). In MySQL, you can do this as:

SELECT substring_index(description, ':', 1) as make,
       substring_index(description, ':', 2) as model,
       count(description) AS sales_count, SUM(amount) AS total_amount
FROM car_sales cs
GROUP BY substring_index(description, ':', 1),
         substring_index(description, ':', 2) with rollup;

This is not exactly the output you are requesting. This puts the make and model in separate columns, and includes an overall total.

You cannot use order by with rollup , alas. You can do this if you use a subquery. However, that probably won't do what you want, because it will order all the rows, including the ones with the summary values.