计算年初至今和上一年年初至今

Question

I want to calculate YTD (1st Jan 2016 to last date of a month) & Prev year YTD (1st Jan 2015 to last date of a month) for each Client.

Below is the SQL Query that i have attempted, but here i get two rows for each Client instead of 1 as I'm using 'CASE WHEN'.

My question is how can i get the result in just one row per Client instead of one row for YTD & another row for YTD-1 for each client?

SELECT [ClientName]
, (CASE WHEN YEAR([Purchase_Date]) = YEAR(GETDATE())-1 THEN (count(Activity)) end) AS 'YTD-1'
, (CASE WHEN YEAR([Purchase_Date]) = YEAR(GETDATE()) THEN (count(Activity)) end) AS 'YTD'
FROM Purchases
WHERE MONTH([Purchase_Date]) <= MONTH(GETDATE())
GROUP BY [ClientName], YEAR([Purchase_Date])
ORDER BY 1

Kindly Help!

Thanks, Ramesh

Answer 1

Remove YEAR([Purchase_Date]) from the GROUP BY part.

Also, instead of:

(CASE WHEN YEAR([Purchase_Date]) = YEAR(GETDATE())-1 THEN (count(Activity)) end) AS 'YTD-1'

use:

count(CASE WHEN YEAR([Purchase_Date]) = YEAR(GETDATE())-1 THEN Activity else NULL end) AS 'YTD-1'

And the same for 'YTD' column.