Append queries dynamically in Power Query

Hi Alex_Ooi ,

please try this:

let
// To make it easy to paste here, I've included the function that's been called in the query itself
// but this would probably be a function that you're going to define a function separately that replicates the queries for your Sales Batch queries (using 2 parameters: Start and End date) 
myFunction = (myStart as text, myEnd as text) => 

let
Source = Value.NativeQuery(PostgreSQL.Database("MyHost", "DatabaseName"), "SELECT
""Site Name"", ""Booking ID"", ""Booking Date""
// truncated for simplicity of presentation
FROM dbo.""MyView""
WHERE ""Booking Date"" >= ' " & myStart & "' AND ""Booking Date"" < ' " & myEnd & "'",
null, [EnableFolding = false])
in
Source
,

// Sample data, replace by a table of your own
Source= Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjDUByIjA0NzJR0lY0N9QyMIJ1YHSc4CWc5CKTYWAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Start = _t, End = _t]),
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Start", type date}, {"End", type date}}),
AddStartString = Table.AddColumn(#"Changed Type", "StartString", each Text.From(Date.Year([Start])) & "-" & Text.PadStart(Text.From(Date.Month([Start])),2,"0") & "-" & Text.PadStart(Text.From(Date.Day([Start])),2,"0")),
AddEndString = Table.AddColumn(AddStartString, "EndString", each Text.From(Date.Year([End])) & "-" & Text.PadStart(Text.From(Date.Month([End])),2,"0") & "-" & Text.PadStart(Text.From(Date.Day([End])),2,"0")),

// Function.InvokeAfter is optional, adjust duration if necessary
CallFunction = Table.AddColumn(AddEndString, "Custom", each Function.InvokeAfter(() => myFunction([StartString], [EndString]), #duration(0,0,0,5)))
in
CallFunction

 I'm a bit surprised that you're setting the "enable folding"-parameter to false. (But maybe this will just be ignored..)