Transposing data ( calculating monthly sales data) in sql - sql

Question

My data has total 100 rows
Day Item Price Unit
01/01/17 jeans 15 4
01/02/17 shirt 10 3
01/01/17 skirt 20 7
01/04/17 skirt 25 1
02/01/17 jeans 5 4
02/02/17 shirt 15 3
02/01/17 skirt 24 7
03/04/17 skirt 25 5
I want ro represent my data as monthly sale by item in january and february
data should represent as
month jeans skirt shirt total
Jan
Feb
I am getting error in my code
SELECT MONTH,
MAX(CASE WHEN ITEM = 'JEANS' THEN GRANDTOTAL END) GRANDTOTAL,
MAX(CASE WHEN ITEM = 'SHIRT' THEN GRANDTOTAL END) AS GRANDTOTAL,
MAX(CASE WHEN ITEM = 'SKIRT' THEN GRANDTOTAL END) AS GRANDTOTAL,
FROM SALES
GROUP BY MONTH ;
I tried all methods but getting error, please help :)

Answer 1

Sales per item is defined as the sum of price x unit while total sales is the sum of sales for all items.
see demo:
http://sqlfiddle.com/#!9/2a9e8f/1
SELECT date_format(day, '%b') as `month`,
sum(case when item='jeans' then price*unit else 0 end) as jeans,
sum(case when item='shirt' then price*unit else 0 end) as shirts,
sum(case when item='skirt' then price*unit else 0 end) as skirts,
sum(price*unit) as total
FROM myTbl
where month(day) <= 2
GROUP BY date_format(day, '%b')
ORDER BY month(day);
result:
month jeans shirts skirts total
Jan 60 30 165 255
Feb 20 45 168 233