Multiple date row data

Hi frederic_FAURE , check this:

Output

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("bdFLCsAgDATQqxTXRUz81Xt0Jy57gvb+tFIwDMxy5GWEpHd3XvfjdqfVb+I3DZq+FMXS2BeaT8tos4QmQk+kJpkJltBk6MnUFOgp1FToqdQcYA5qGvzVqJGASwxcCVQJ37UodvFt/7MZrpbp1aapFsZ4AQ==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [EmpName = _t, start = _t, end = _t]),
    ChangedType = Table.TransformColumnTypes(Source,{{"EmpName", type text}, {"start", type date}, {"end", type date}}),
    RenamedColumns = Table.RenameColumns(ChangedType,{{"start", "startDate"}, {"end", "endDate"}}),
    GroupedRows = Table.Group(RenamedColumns, {"EmpName", "startDate"}, {{"start", each List.Min([startDate]), type date}, {"end", each List.Max([endDate]), type date}}, 0,
        (x,y)=> Value.Compare(Date.StartOfYear(y[startDate]), Date.StartOfYear(x[startDate])) ),
    RemovedColumns = Table.RemoveColumns(GroupedRows,{"startDate"})
in
    RemovedColumns

This is the proces for solving your problem, consider the below table (column Start and end are in type Date)

select start column and from add column tab, Date section, pick Year (as below)

then select the column EmpName and Year (added by the previous step) and from home tab pick group by command and make the below setting

it solve the problem and results in