Selecting last date available and one before last - sql

Question

I have a table #sales in which I record sales and profits
The select below gives me the summary of sales and profits for 2 specific dates
The challenge is as follows:
Instead of hard-coding the date, I would need to replace it with:
First date: get the last available date. I though of using max(fecha_valor) but I get an error.
Second date: the one before last available date
so in the example below would be:
First date: '20140714'
Second date: '20140712'
Is it possible to have an additional column with columna_1_p / columna_1 ?
Can anyone help with this?
DECLARE #sales TABLE
(
custom VARCHAR(10) NOT NULL,
fecha_valor DATE NOT NULL,
sales NUMERIC(10, 2) NOT NULL,
profits NUMERIC(10, 2) NOT NULL
);
INSERT INTO #sales(Custom, Fecha_valor, sales, profits)
VALUES ('q', '20140708', 51,21),
('q', '20140712', 3,33),
('q', '20140712', 5,12),
('q', '20140711', 6,43),
('q', '20140712', 2,66),
('q', '20140712', 7,21),
('q', '20140714', 24,76),
('q', '20140714', 24,12),
('x', '20140709', 25,0),
('x', '20140710', 16,0),
('x', '20140711', 66,31),
('x', '20140712', 23,12),
('x', '20140712', 35,11),
('x', '20140714', 57,1),
('c', '20140712', 97,2),
('c', '20140714', 71,3);
SELECT
custom,
CAST(SUM(Case fecha_valor when '2014-07-12' then sales ELSE 0 END) AS numeric(12, 3)) as columna_1,
CAST(SUM(Case fecha_valor when '2014-07-14' then sales ELSE 0 END) AS numeric(12, 3)) as columna_2,
CAST(SUM(Case fecha_valor when '2014-07-12' then profits ELSE 0 END) AS numeric(12, 3)) as columna_1_P,
CAST(SUM(Case fecha_valor when '2014-07-14' then profits ELSE 0 END) AS numeric(12, 3)) as columna_2_P
FROM
#sales
GROUP BY
custom;

Answer 1

You can use following query:
DECLARE #FirstDate DATE,
#SecondDate DATE
SELECT #FirstDate = MAX(fecha_valor) FROM #Sales
SELECT #SecondDate = MAX(fecha_valor) FROM #Sales WHERE fecha_valor<> #FirstDate
SELECT custom,
CAST(SUM(Case fecha_valor when #SecondDate THEN sales ELSE 0 END) AS numeric(12, 3)) as columna_1,
CAST(SUM(Case fecha_valor when #FirstDate THEN sales ELSE 0 END) AS numeric(12, 3)) as columna_2,
CAST(SUM(Case fecha_valor when #SecondDate THEN profits ELSE 0 END) AS numeric(12, 3)) as columna_1_P,
CAST(SUM(Case fecha_valor when #FirstDate THEN profits ELSE 0 END) AS numeric(12, 3)) as columna_2_P
FROM #sales
GROUP BY custom;

Answer 2

Not sure on what exactly you are looking for in your final result but would something along the lines of the below work?
SELECT Custom, Fecha_valor, sales, profits FROM sales ORDER BY Fecha_valor DESC LIMIT 2