Ms Access - Combine Non-null Column Values Into A (column Name: Column Value) Text String / Field

I have an Excel file that's basically a query result to a database server. I linked one sheet of this Excel file as an external table from within a MS Access database. This externa

Solution 1:

Silly me.

MS Access requires commas as parameter separator, not semicolons.

Hence the following query works:

SELECT
  id,
  Iif([param_foo]="Null", "", "; param_foo: "&[param_foo])
& Iif([param_bar]="Null", "", "; param_bar: "&[param_bar])
& Iif([param_baz]="Null", "", "; param_baz: "&[param_baz]) AS all_parameters
FROM
  my_table
;

Problem solved.