Compare the evolution in a period between two years (ex. between Decembre 2017 and March 2018
I can create a table with data between some months Inside 2 years but I can't compare the result with the same previous year (ex compaare results from Dec 2017 to March 2018 with results from Dec 2016 to March 2017
Paul Cooper commented
You should be able to do this by using two queries you join. Query 1 would have the later set of data aggregated by a grouped date field (first day of month in your case). In this query add a new column Last Year Date that is the date fields (first day of month) minus 1 year. In Query 2 you would have the equivalent aggregation but no need to add the new date field. Now you should merge the two using the Last Year Date from Query 1 and the grouped date field in Query 2. Now the data should be side by side in two columns. You can create comparison fields from these two columns.
Having said that if you are looking for an easier way to do this say in DAX where you are able to pick the grouping relative to the current grouping to aggregate using a currently non-existent RELATEDGROUP function (which would be similar to CURRENTGROUP but useable outside of GROUPBY )
RELATEDGROUP(<grouping_field1>, <expression1>[, <grouping_field2>, <expression2>[, ...]])
SUM([Sales]) - SUMX(RELATEDGROUP([MonthOfSalesDate],PREVIOUSYEAR([MonthOfSalesDate])), [Sales])
(which would get the difference between this year's month sum and last year's) then that would make life easier as that could let you get comparisons in a single measure without the need to create secondary tables/queries to join together.