SQL - 2 table values to be grouped by third unconnected value - sql

Question

I want to create a graph that pulls data from 2 user questions generated from within an SQL database.
The issue is that the user questions are stored in the same table, as are the answers. The only connection is that the question string includes a year value, which I extract using the LEFT command so that I output a column called 'YEAR' with a list of integer values running from 2013 to 2038 (25 year period).
I then want to pull the corresponding answers ('forecast' and 'actual') from each 'YEAR' so that I can plot a graph with a couple of values from each year (sorry if this isn't making any sense). The graph should show a forecast line covering the 25 year period with a second line (or column) showing the actual value as it gets populated over the years. I'll then be able to visualise if our actual value is close to our original forecast figures (long term goal!)
CODE BELOW
SELECT CAST((LEFT(F_TASK_ANS.TA_ANS_QUESTION,4)) AS INTEGER) AS YEAR,
-- first select takes left 4 characters of question and outputs value as string then coverts value to whole number.
CAST((CASE WHEN F_TASK_ANS.TA_ANS_QUESTION LIKE '%forecast' THEN F_TASK_ANS.TA_ANS_ANSWER END) AS NUMERIC(9,2)) AS 'FORECAST',
CAST((CASE WHEN F_TASK_ANS.TA_ANS_QUESTION LIKE '%actual' THEN ISNULL(F_TASK_ANS.TA_ANS_ANSWER,0) END) AS NUMERIC(9,2)) AS 'ACTUAL'
-- actual value will be null until filled in each year therefore ISNULL added to replace null with 0.00.
FROM F_TASK_ANS INNER JOIN F_TASKS ON F_TASK_ANS.TA_ANS_FKEY_TA_SEQ = F_TASKS.TA_SEQ
WHERE TA_ANS_ANSWER <> ''
AND (TA_TASK_ID LIKE '%6051' OR TA_TASK_ID LIKE '%6052')
-- The two numbers above refer to separate PPM questions that the user enters a value into
I tried GROUP BY 'YEAR' but I get an
Error: Each GROUP BY expression must contain at least one column that
is not an outer reference - which I assume is because I haven't linked
the 2 tables in any way...
Should I be adding a UNION so the tables are joined?
What I want to see is something like the following output (which I'll graph up later)
YEAR FORECAST ACTUAL
2013 135000 127331
2014 143000 145102
2015 149000 0
2016 158000 0
2017 161000 0
2018... etc
Any help or guidance would be hugely appreciated.
Thanks

Answer 1

Although the syntax is pretty hairy, this seems like a fairly simple query. You are in fact linking your two tables (with the JOIN statement) and you don't need a UNION.
Try something like this (using a common table expression, or CTE, to make the grouping clearer, and changing the syntax for slightly greater clarity):
WITH data
AS (
SELECT YEAR = CAST((LEFT(A.TA_ANS_QUESTION,4)) AS INTEGER)
, FORECAST = CASE WHEN A.TA_ANS_QUESTION LIKE '%forecast'
THEN CONVERT(NUMERIC(9,2), A.TA_ANS_ANSWER)
ELSE CONVERT(NUMERIC(9,2), 0)
END
, ACTUAL = CASE WHEN A.TA_ANS_QUESTION LIKE '%actual'
THEN CONVERT(NUMERIC(9,2), ISNULL(A.TA_ANS_ANSWER,0) )
ELSE CONVERT(NUMERIC(9,2), 0)
END
FROM F_TASK_ANS A
INNER JOIN F_TASKS T
ON A.TA_ANS_FKEY_TA_SEQ = T.TA_SEQ
-- It sounded like you wanted to include the ones where the answer was null. If
-- that's wrong, get rid of the test for NULL.
WHERE (A.TA_ANS_ANSWER <> '' OR A.TA_ANS_ANSWER IS NULL)
AND (TA_TASK_ID LIKE '%6051' OR TA_TASK_ID LIKE '%6052')
)
SELECT YEAR
, FORECAST = SUM(data.Forecast)
, ACTUAL = SUM(data.Actual)
FROM data
GROUP BY YEAR
ORDER BY YEAR

Answer 2

Try something like this ...
SELECT CAST((LEFT(F_TASK_ANS.TA_ANS_QUESTION,4)) AS INT) AS [YEAR]
,SUM(CAST((CASE WHEN F_TASK_ANS.TA_ANS_QUESTION LIKE '%forecast'
THEN F_TASK_ANS.TA_ANS_ANSWER ELSE 0 END) AS NUMERIC(9,2))) AS [FORECAST]
,SUM(CAST((CASE WHEN F_TASK_ANS.TA_ANS_QUESTION LIKE '%actual'
THEN F_TASK_ANS.TA_ANS_ANSWER ELSE 0 END) AS NUMERIC(9,2))) AS [ACTUAL]
FROM F_TASK_ANS INNER JOIN F_TASKS
ON F_TASK_ANS.TA_ANS_FKEY_TA_SEQ = F_TASKS.TA_SEQ
WHERE TA_ANS_ANSWER <> ''
AND (TA_TASK_ID LIKE '%6051' OR TA_TASK_ID LIKE '%6052')
GROUP BY CAST((LEFT(F_TASK_ANS.TA_ANS_QUESTION,4)) AS INT)