SQL按季度和年度分组

Question

I'm working on a project that is kinda interesting at least to me... Right now I have this code. While this works, what I'd like to present is one row for all of 2016 and the quarters of 2017 broken out.

SELECT account_id,
  quarter, revenue,
  sum(case when quarter like '%2016' then revenue else 0 end) as rev2016
FROM prescreen
GROUP BY quarter
ORDER BY rev2016 desc ;

What I am seeing is

account_id .   quarter .   revenue .   rev2016
         1     Q4-2016 .        600 .      600
         1     Q1-2016          500 .      500
         1     Q2-2016          400        400
         1     Q3-2016          350 .      350
         1     Q1-2017         1000 .      0
         1     Q2-2017 .        650 .      0
         1     Q3-2017          890 .      0

The expected output that I'd like to see is more like

account_id .   rev2016 .   Q1-2017 .   Q2-2017 .   Q3-2017
1 .            1850 .      1000 .       650 .       890

What else can I try to get to a one line result here?

Answer 1

In MySQL, you normally pivot by doing conditional aggregation:

SELECT account_id,
       (case when quarter like '2016%' then revenue else 0 end) as rev_2016,
       (case when quarter like 'Q1-2017' then revenue else 0 end) as rev_2017Q1,
       . . .
FROM prescreen
GROUP BY account_id;