create date value for each row in a table

Create a new Blank Query with

= List.Dates(#date(2021,01,01), 365, #duration(1,0,0,0))

That will give you a list of dates. Give it a name.

Convert to table.

Change to date type.

Filter the dates with :

= Table.SelectRows(#"Changed Type", each Date.Day([Column1]) = 1)

(substitute your step name and column name in that)

---

In the original table, Add a custom column (type # and the name of the query should autocomplete)

Then expand the column from the column header.

Good luck

Hello Zabeer 

add a new column with this formula

List.Transform(List.Numbers(1,12), each #date(2021,_,1))

and then expand the list-column to new rows. Here the complete example

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclTSUTI2MzAwUIrViVZyAvJMLMC8WAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Name = _t, Value = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Name", type text}, {"Value", Int64.Type}}),
    AddMonths = Table.AddColumn
    (
        #"Changed Type",
        "MonthsList",
        each List.Transform(List.Numbers(1,12), each #date(2021,_,1))
    ),
    #"Expanded MonthsList" = Table.ExpandListColumn(AddMonths, "MonthsList")
in
    #"Expanded MonthsList"

this transforms this

into this

Copy paste this code to the advanced editor in a new blank query to see how the solution works.

If this post helps or solves your problem, please mark it as solution (to help other users find useful content and to acknowledge the work of users that helped you)
Kudoes are nice too

Have fun

Jimmy

Hi Zabeer ,

If you also want to add each days of each months, please try this:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclTSUTI2MzAwUIrViVZyAvJMLMC8WAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Name = _t, Value = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Name", type text}, {"Value", Int64.Type}}),
    AddDays = Table.AddColumn(#"Changed Type", "DaysList", each let 
StartDate = #date(2021,01,01),
EndDate = #date(2021,12,31),
DurationDays = Duration.Days( EndDate-StartDate)
in 
List.Dates(StartDate, DurationDays, #duration(1,0,0,0))),
    #"Expanded DaysList" = Table.ExpandListColumn(AddDays, "DaysList")
in
    #"Expanded DaysList"

Best Regards,

Icey

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.