Question

How can I combine two select queries for the same table, which have two different where in Sqlite?

I have a table with more than 10k rows. Two example rows looks like this:

year | project | finance | flow
1990 | water   | 300500  | grant
1999 | energy  | 200500  | loan

My attempt does not work:

SELECT sum(finance), (select sum(finance) from table where flow = grant) 
FROM table where flow = loan group by year 

The result should have all results group by year and list the sum(budget) in a column for grants and a column for loans.

year | grant | loan
1990 | 62662 | 383983
1991 | 28928 | 278272

UPDATE: The first example did not correspond correctly to my use case. I had to change it.

Answer 1

In this case, use CASE:

 SELECT year, 
        SUM(CASE WHEN flow = 'grant' THEN finance ELSE 0 END) AS grant_total, 
        SUM(CASE WHEN flow = 'loan' THEN finance ELSE 0 END) AS loan_total
 FROM your_table 
 GROUP BY year

The logic is different than what you outlined (it’s a single SELECT with a single WHERE clause) but it will effectively pivot the data you need from rows to columns.