Problems with format dates entered

Hi Eddistoff ,

Add this as a new custom column to restate the approval date in the correct format:

let
    __cDate = Date.AddMonths(Date.From([Date of registration]), 1)
in
    if Date.From([Date of approval]) < Date.From([Date of registration]) or Date.From([Date of approval]) > __cDate
    then Text.Combine(
        {
            Text.Middle([Date of approval], 3, 2),
            Text.Start([Date of approval], 2),
            Text.End([Date of approval], 4)
        },
        "/"
    )
    else [Date of approval]

From here you can change the data type of your new column to Date Type and perform your calculation.

Example as working query:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("jZBBC8IwDIX/S88bTdLMrWd33Vlk7CTizUHx/+Mrri4HpSuENo98fUnm2ZF66ryQiGscI5DtwnlN6X574TWO7TS1Vxy3NMCip6FU5UDGVIRLWp8P3CDA7ZAaKGQIv2gNYk9SanRrUA41+B2j27BY8wLUl5pTXggZ4b9XMF79x6u6DA5mjCF76ZG5hM3KYl6+GOE3trwB", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Date of registration" = _t, Product = _t, #"Date of approval" = _t, #"Comments " = _t, #"Format entered" = _t]),
    chgRegDateType = Table.TransformColumnTypes(Source,{{"Date of registration", type date}}),
    addDtApproval =
    Table.AddColumn(
        chgRegDateType,
        "dtApproval", each
        let
            __cDate = Date.AddMonths(Date.From([Date of registration]), 1)
        in
        if Date.From([Date of approval]) < Date.From([Date of registration]) or Date.From([Date of approval]) > __cDate
        then Text.Combine(
            {
                Text.Middle([Date of approval], 3, 2),
                Text.Start([Date of approval], 2),
                Text.End([Date of approval], 4)
            },
            "/"
        )
        else [Date of approval]
    )
in
    addDtApproval

Working query output:

Pete