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Revenue by Vertical

mediumSQLJoinsGroupByNULLs

Loopwire's sales VP is convinced healthcare customers pay more than anyone else and wants the budget shifted accordingly. The way to test that is live monthly billing broken down by the customer's sector. The difficulty is that the two facts live apart: the contract knows what it bills but not who the customer is beyond an id number, and the sector tag sits on the customer record. MRR — monthly recurring revenue — is what a live contract bills each month.

subscriptions — one row per contract. account_id points at a row in accounts. plan is the tier the customer bought. mrr is what that contract bills every month, in dollars. start_date is the day it began. A contract that has stopped carries the day it stopped in end_date; one that is still running has nothing there, shown as below and stored as NULL.

id account_id plan mrr start_date end_date
1 1 starter 49 2022-11-03 2023-02-03
2 1 growth 149 2023-02-03
3 2 growth 149 2022-12-15 2023-06-15
4 3 starter 49 2023-01-31
5 4 growth 149 2023-02-06
6 5 enterprise 499 2023-02-22
7 6 starter 49 2023-03-01 2023-04-01
8 7 growth 149 2023-03-22
9 8 enterprise 499 2023-04-28
10 2 starter 49 2023-06-15

accounts — one row per customer company. industry is the sector that company works in; signup_date is the day it created its Loopwire account.

id company_name industry signup_date
1 Northwind Traders retail 2022-11-03
2 Vertex Analytics software 2022-12-15
3 Bluepeak Logistics logistics 2023-01-20
4 Fernwood Studio media 2023-02-05
5 Cobalt Health healthcare 2023-02-18
6 Ridgeline Capital finance 2023-03-01
7 Sable & Co retail 2023-03-22
8 Hearth Robotics manufacturing 2023-04-10

Both tables already exist in the database — there is nothing to create or load.

Task: Write a query that returns one row per industry, with columns industry and mrr_total, mrr_total being the combined monthly billing of that industry's still-running contracts. An industry with no running contract does not appear. Largest total first; equal totals are listed alphabetically by industry name.

Example output

Shape only — these sectors and figures are invented:

industry mrr_total
energy 1180
education 640
hospitality 640
insurance 300
nonprofit 75

(...1 more row not shown)

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