I'd like to generate a list of dates with the hopes of joining with another table, but I don't know what syntax to use, something similar to this:
SELECT dates.date, transactions.account_id, transactions.amount
FROM (...) as dates
LEFT JOIN transactions ON transactions.date = dates.date
WHERE dates.date >= '2010-01-01' AND dates.date <= '2010-12-31'
ORDER BY dates.date;
I want the dates so I don't have to further massage the data client-side. I'm using this to display a table similar to this:
Account 2010-01-01 2010-01-02 2010-01-03 Balance
============================================================
Chase 123 +100 -20 -70 +10
Chase 231 +13 -9 +4
Use the generate_series function to get a list of numbers that you can add to a date in order to get a list of dates:
SELECT CURRENT_DATE + s.a AS dates
FROM generate_series(0,14,7) as s(a);
Result:
dates
------------
2004-02-05
2004-02-12
2004-02-19
The latter part of your question deals with pivoting the result set -- converting row data into columnar data. PIVOT and UNPIVOT are ANSI, but I don't see them as supported by PostgreSQL currently. The most consistently supported means of pivoting a query is to use aggregate functions:
SELECT t.account,
SUM(CASE WHEN t.date = '2010-01-01' THEN t.amount END) AS '2010-01-01',
SUM(CASE WHEN t.date = '2010-01-02' THEN t.amount END) AS '2010-01-02',
SUM(CASE WHEN t.date = '2010-01-03' THEN t.amount END) AS '2010-01-03',
SUM(t.amount) AS Balance
FROM (SELECT CURRENT_DATE + s.a AS dates
FROM generate_series(0,14,7) as s(a)) x
LEFT JOIN TRANSACTIONS y ON y.date = x.date
GROUP BY t.account
...means dynamic SQL.