substring: row information to field names - sqlite

Question

I have information in an SQLite database. The database structure can not be changed.
I am trying to construct a query that will give me a result in which the TypeOfInformation entries are field names:
My first try was to work with subqueries:
SELECT (SELECT Value FROM FinData WHERE Type = 'Price') AS Price,
(SELECT Value FROM FinData WHERE Type = 'Volume') AS Volume
FROM FinData")
Seemed perfect, however, the result was a resultset in which EVERY entry in the columns Price and Volume are equal to the FIRST respective entry of Price and Volume in the original database:
I tried to get around this and to include the other Price and Volume information ­- but I failed. (Which is a pity, because the syntax seemed somehow easy to grasp.)
Next try was the following:
Select Date, Value AS Volume From FinData WHERE Volume IN
(SELECT Value FROM FinData WHERE (Type = 'Volume'))
This gives me a resultset with a Volume column and all volume information. Okay, so far. However, when I want to complement this resultset which a Price column via
Select Date, Value AS Volume From FinData WHERE Volume IN
(SELECT Value FROM FinData WHERE (Type = 'Volume'))
union
Select Date, Value AS Close From FinData WHERE Price IN
(SELECT Value FROM FinData WHERE (Type = 'Price'))
I get a resultset that shows Price and Volume information in only ONE column ("Volume"), which therefore is also useless.

Answer 1

To look up a value corresponding to a row in the outer query, you have to use a correlated subquery, which explicitly makes a connection between both:
SELECT Date,
(SELECT Value
FROM FinData
WHERE Date = Dates.Date
AND TypeOfInformation = 'Price'
) AS Price,
(SELECT Value
FROM FinData
WHERE Date = Dates.Date
AND TypeOfInformation = 'Volume'
) AS Volume
FROM (SELECT DISTINCT Date
FROM FinData) AS Dates;
(The DISTINCT subquery is used to prevent multiple rows for each date.)
Alternatively, group all rows for a date, and use aggregation functions and CASE expressions to extract the values from the proper rows:
SELECT Date,
MAX(CASE WHEN TypeOfInformation = 'Price' THEN Value END) AS Price,
MAX(CASE WHEN TypeOfInformation = 'Volume' THEN Value END) AS Volume
FROM FinData
GROUP BY Date;

Answer 2

Assuming dates are unique per price volume pair, you can do this:
with xxx(date,price,volume) as
(
select date,value,0 from findata where typeofinformation = 'Price'
union
select date,0,value from findata where typeofinformation = 'Volume'
)
select date,sum(price) price,sum(volume) volume from xxx group by date;