Sorting data by YEAR - sql

Question

I am completely new to SQL and have really only run statements with minimal modifications. I am currently trying to modify this specific query:
SELECT DISTINCT (ROUND (windspeed * 2, -1) / 2) AS wndspd,
SUM (CASE WHEN month = 1 THEN 1 ELSE NULL END) AS January,
SUM (CASE WHEN month = 2 THEN 1 ELSE NULL END) AS February,
SUM (CASE WHEN month = 3 THEN 1 ELSE NULL END) AS March,
SUM (CASE WHEN month = 4 THEN 1 ELSE NULL END) AS April,
SUM (CASE WHEN month = 5 THEN 1 ELSE NULL END) AS May,
SUM (CASE WHEN month = 6 THEN 1 ELSE NULL END) AS June,
SUM (CASE WHEN month = 7 THEN 1 ELSE NULL END) AS July,
SUM (CASE WHEN month = 8 THEN 1 ELSE NULL END) AS August,
SUM (CASE WHEN month = 9 THEN 1 ELSE NULL END) AS September,
SUM (CASE WHEN month = 10 THEN 1 ELSE NULL END) AS October,
SUM (CASE WHEN month = 11 THEN 1 ELSE NULL END) AS November,
SUM (CASE WHEN month = 12 THEN 1 ELSE NULL END) AS December
FROM table1
WHERE platformid = 'coollocation'
AND networktype = 'typeofcoollocation'
AND (windspeedqc <> '2' OR windspeedqc IS NULL)
GROUP BY ROUND (windspeed * 2, -1) / 2
ORDER BY ROUND (windspeed * 2, -1) / 2;
What I want from the query is to instead of sorting by months, sort by all the years that are available for the specific location (platformid). So far I have just modified the script so that it looks like this:
SELECT DISTINCT
(ROUND (windspeed * 2, -1) / 2) AS wndspd,
SUM (
CASE
WHEN TO_CHAR (observationtime, 'YYYY') = 1957 THEN 1
ELSE NULL
END)
AS given_year,
SUM (
CASE
WHEN TO_CHAR (observationtime, 'YYYY') = 1958 THEN 1
ELSE NULL
END)
AS GIVEN_YEAR2
FROM table1
WHERE platformid = 'coollocation'
AND networktype = 'typeofcoollocation'
AND (windspeedqc <> '2' OR windspeedqc IS NULL)
GROUP BY ROUND (windspeed * 2, -1) / 2
ORDER BY ROUND (windspeed * 2, -1) / 2;
The problem is that I know that the years go from 1957-2015. I'm pretty sure that there is a more efficient way to list out the information that I want without creating a specific SUM string for every single year. I have no idea how to do that however. Please help!

Answer 1

You can try creating a PIVOT query
SELECT wndspd, [1957], [1958], [1959],...etc....[2013], [2014], [2015] FROM
(
SELECT (ROUND (windspeed * 2, -1) / 2) AS wndspd,
YEAR(observationtime) yr
FROM table1
WHERE platformid = 'coollocation'
AND networktype = 'typeofcoollocation'
AND (windspeedqc <> '2' OR windspeedqc IS NULL)
) src
PIVOT (
COUNT(yr)
FOR yr IN ([1957],[1958], [1959],...etc....[2013], [2014], [2015])
) pvt
you'll have to fill in all of the other years between 1959 and 2013.
here's an easier way to create all of the columns from 1957 to the current year.
DECLARE #PivotCols VARCHAR(MAX),
#MinYear INT = 1957,
#CurYear INT = YEAR(GETDATE())
WHILE #MinYear < #CurYear
BEGIN
SET #PivotCols = COALESCE( #PivotCols + '],[', '[') + CONVERT(VARCHAR, #MinYear)
SET #MinYear = #MinYear + 1
END
SET #PivotCols = CONCAT(#PivotCols,'],[',CONVERT(VARCHAR, #MinYear),']')
DECLARE #Sql VARCHAR(MAX) = '
SELECT wndspd, ' + #PivotCols + ' FROM
(
SELECT (ROUND (windspeed * 2, -1) / 2) AS wndspd,
YEAR(observationtime) yr
FROM table1
WHERE platformid = ''coollocation''
AND networktype = ''typeofcoollocation''
AND (windspeedqc <> ''2'' OR windspeedqc IS NULL)
) src
PIVOT (
COUNT(yr)
FOR yr IN (' + #PivotCols + ')
) pvt
'
EXEC (#Sql)

Answer 2

I think you are essentially trying to do this:
SELECT DISTINCT (ROUND (windspeed * 2, -1) / 2) AS wndspd
,TO_CHAR(observationtime, 'YYYY') as year,
,COUNT(1) as occurrences
FROM table1
WHERE platformid = 'coollocation'
AND networktype = 'typeofcoollocation'
AND (windspeedqc <> '2' OR windspeedqc IS NULL)
GROUP BY (ROUND(windspeed * 2, -1) / 2), TO_CHAR(observationtime, 'YYYY')
ORDER BY 1, 2;
...however the count of occurrences in each year would then be represented by a row instead of a column.
Unfortunately there is no easy way to pivot the rows in this query into columns because you fundamentally need to know how many columns there are and ensure each row has the values populated properly.
At the end of the day you'll need to add a line for each year to your SELECT clause. It could look like this:
SELECT yearly.wndspd
,SUM(CASE WHEN yearly.year='1957' THEN yearly.occurrences ELSE 0 END) as 1957
,SUM(CASE WHEN yearly.year='1958' THEN yearly.occurrences ELSE 0 END) as 1958
...
,SUM(CASE WHEN yearly.year='2015' THEN yearly.occurrences ELSE 0 END) as 2015
FROM
(SELECT DISTINCT (ROUND (windspeed * 2, -1) / 2) AS wndspd
,TO_CHAR(observationtime, 'YYYY') as year,
,COUNT(1) as occurrences
FROM table1
WHERE platformid = 'coollocation'
AND networktype = 'typeofcoollocation'
AND (windspeedqc <> '2' OR windspeedqc IS NULL)
GROUP BY (ROUND(windspeed * 2, -1) / 2), TO_CHAR(observationtime, 'YYYY')) yearly
GROUP BY yearly.wndspd
ORDER BY 1, 2;