Date Format for New Column not working for all rows

[zhsin]

Hi,

Can someone advise me what is wrong with this? The calculation works for some rows but not all. I tried to remove the - sign to add 1 month, then the opposite will appear with the date + 1 month, but those rows that are visible in - 1 will then be blank.

What I need is to reduce the month by 1 for all Bill Date.

[zhsin · Accepted solution]

Realized I can get the same at Query Editor.

#"Added Custom1" = Table.AddColumn(#"Added Custom", "YYYYMM", each Date.ToText(Date.AddMonths([Bill Date],-1),"yyyyMM")),