How to enter a initial value to calculate inventory in Power Query or DAX

Hi Anonymous 

You can create a blank query and put the follwing code to advanced editor in power query

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("bc7bCcAwCAXQXfwOxCe1swT3X6MmloJQUIR74OJawMgyaRIMcETMUxvjM80gx/wwMTa1UuGjal2vUpJS73qXsv0201tNxbrfi3gA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Inventory = _t, #" Product Qty used" = _t, #"Product arrived " = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Date", type date}, {"Inventory", Int64.Type}, {" Product Qty used", Int64.Type}, {"Product arrived ", Int64.Type}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 1, 1, Int64.Type),
    #"Added Custom" = Table.AddColumn(#"Added Index", "Custom", each List.Sum(Table.SelectRows(#"Added Index",(x)=>x[Index]<=[Index])[#" Product Qty used"])),
    #"Added Custom1" = Table.AddColumn(#"Added Custom", "Custom.1", each List.Sum(Table.SelectRows(#"Added Index",(x)=>x[Index]<=[Index])[#"Product arrived "])),
    #"Added Custom2" = Table.AddColumn(#"Added Custom1", "Final", each if [Index]=1 then [Inventory] else List.Min(Table.SelectRows(#"Added Custom1",(x)=>x[Index]=1)[Inventory])-[Custom]+[Custom.1]),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom2",{"Index", "Custom", "Custom.1"})
in
    #"Removed Columns"

Output

Best Regards!

Yolo Zhu

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