Get list of counts by date - sql

Question

I have two tables. One containing a list of applications. And another one containing counts associated to them every week. Now I want to get as a result the app name and the count for this week and the previous. Let me explain this.
app:
+----+-------------+
| id | name |
+----+-------------+
| 1 | Office 2007 |
+----+-------------+
| 2 | Office 2010 |
+----+-------------+
| 3 | Office 2013 |
+----+-------------+
count:
+----+--------+-------+------------+
| id | app_id | count | date |
+----+--------+-------+------------+
| 1 | 1 | 200 | 2016-01-11 |
+----+--------+-------+------------+
| 2 | 2 | 500 | 2016-01-11 |
+----+--------+-------+------------+
| 3 | 3 | 750 | 2016-01-11 |
+----+--------+-------+------------+
| 4 | 1 | 180 | 2016-01-18 |
+----+--------+-------+------------+
| 5 | 2 | 378 | 2016-01-18 |
+----+--------+-------+------------+
| 6 | 3 | 1000 | 2016-01-18 |
+----+--------+-------+------------+
And this is the result I need. I need all the applications with the count of this week and the previous:
+-------------+-----------------+-----------------+
| app | count_this_week | count_prev_week |
+-------------+-----------------+-----------------+
| Office 2007 | 180 | 200 |
+-------------+-----------------+-----------------+
| Office 2010 | 378 | 500 |
+-------------+-----------------+-----------------+
| Office 2013 | 1000 | 750 |
+-------------+-----------------+-----------------+
A script runs every week which fills the count table. And now I need to get a report also on a weekly basis.
Honestly I'm a bit lost as I don't know how to declare the conditions for the columns.

Answer 1

You can try to group first by DATEPART(WEEK,C.date),name and then split the counts into 2 columns using another GROUP BY. Something like this
EDIT
If there are exactly 1 record per week per app, you can do with just one group by like this.
SELECT
appname,
SUM(CASE WHEN weekno = 0 THEN sumcount ELSE 0 END) as thisweek,
SUM(CASE WHEN weekno = 1 THEN sumcount ELSE 0 END) as lastweek
FROM
(
SELECT
DATEPART(WEEK,CURRENT_TIMESTAMP) - DATEPART(WEEK,C.date) as weekno,
name as appname,
count as sumcount
FROM App A
INNER JOIN CountTable C ON A.[id] = C.[app_id]
WHERE DATEPART(WEEK,C.date) BETWEEN DATEPART(WEEK,CURRENT_TIMESTAMP) - 1 AND DATEPART(WEEK,CURRENT_TIMESTAMP)
)T
GROUP BY appname
Query
SELECT
appname,
SUM(CASE WHEN weekno = 0 THEN sumcount ELSE 0 END) as thisweek,
SUM(CASE WHEN weekno = 1 THEN sumcount ELSE 0 END) as lastweek
FROM
(
SELECT
DATEPART(WEEK,CURRENT_TIMESTAMP) - DATEPART(WEEK,C.date) as weekno,
name as appname,
SUM(count) as sumcount
FROM App A INNER JOIN CountTable C ON A.[id] = C.[app_id]
WHERE DATEPART(WEEK,C.date) BETWEEN DATEPART(WEEK,CURRENT_TIMESTAMP) - 1 AND DATEPART(WEEK,CURRENT_TIMESTAMP)
GROUP BY DATEPART(WEEK,C.date),name
) AS T
GROUP BY appname
SQL Fiddle
Output
| appname | thisweek | lastweek |
|-------------|----------|----------|
| Office 2007 | 180 | 200 |
| Office 2010 | 378 | 500 |
| Office 2013 | 1000 | 750 |

Answer 2

You can use this generic query with a variable for the current week day:
DECLARE #week date = '2016-01-18';
WITH data AS (
SELECT a.name, c.[count]
, w = CASE WHEN c.[date] = #week THEN 0 ELSE 1 END
FROM #Counts c
INNER JOIN #Apps a ON c.app_id = a.id
WHERE [date] = #week OR [date] = DATEADD(day, -7, #week)
)
SELECT App = name, count_this_week = [0], count_prev_week = [1]
FROM data d
PIVOT (
MAX([count])
FOR w IN ([0], [1])
) p
Output:
App count_this_week count_prev_week
Office 2007 180 200
Office 2010 378 500
Office 2013 1000 750
Your data:
DECLARE #Apps TABLE ([id] int, [name] varchar(11));
DECLARE #Counts TABLE([id] int, [app_id] int, [count] int, [date] date);
INSERT INTO #Apps([id], [name])
VALUES
(1, 'Office 2007'),
(2, 'Office 2010'),
(3, 'Office 2013')
;
INSERT INTO #Counts([id], [app_id], [count], [date])
VALUES
(1, 1, 200, '2016-01-11'),
(2, 2, 500, '2016-01-11'),
(3, 3, 750, '2016-01-11'),
(4, 1, 180, '2016-01-18'),
(5, 2, 378, '2016-01-18'),
(6, 3, 1000, '2016-01-18')
;

Answer 3

SELECT *
FROM count
JOIN app ON app.id=count.app_id
WHERE date BETWEEN '2016-01-18' AND '2016-01-11'