Merging tables in excel using power query - excel

Question

im using a certain config of tables to generate a cascading dropdown list that looks as such:
I wanna merge these tables to look as such using excels powerquery:

Answer 1

Since each dropdown list is a different table, you have to create a list of all the tables.
Creating a list of tables for PQ to operate on can be tricky.
In my example, they were named Table19 - Table26 so I used the List.Generate function to do that. But there are other ways to generate such a list, including just hard-coding it.
Then it's just a matter of reading in all the tables, unpivoting and expanding.
See the comments in the code for better understanding.
M Code
let
//create a list of the relevant table names
// and create a column of the names
//many ways to do this
//Since mine are table19-26, I do it like this:
tableNames = List.Generate(
()=>[Table Name = "Table" & "19", IDX=20],
each [IDX] < 28,
each [Table Name = "Table" & Text.From([IDX]), IDX = [IDX]+1],
each [Table Name]
),
#"Converted to Table" = Table.FromList(tableNames, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
//Add custom column containing the actual table referred to in column1
//then delete the table names column
#"Added Custom" = Table.AddColumn(#"Converted to Table", "Tables", each Excel.CurrentWorkbook(){[Name=[Column1]]}[Content]),
#"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Column1"}),
//add custom column to unpivot each of the tables
//then remove the original tables column and expand the unpivoted column
#"Added Custom1" = Table.AddColumn(#"Removed Columns", "unPivot", each
Table.UnpivotOtherColumns([Tables],{},"Type","Subtype")),
#"Removed Columns1" = Table.RemoveColumns(#"Added Custom1",{"Tables"}),
#"Expanded unPivot" = Table.ExpandTableColumn(#"Removed Columns1", "unPivot", {"Type", "Subtype"}, {"Type", "Subtype"})
in
#"Expanded unPivot"