Merge Irregular Time Based Data Series

Question

I would like to merge 2 Google sheets (INPUT #1 & INPUT #2) into 1 sheet (OUTPUT). These 3 sheets are enclosed in the same Google Spreadsheet.

On a daily basis, Sheets INPUT #1 & INPUT #2 are updated by the end of the data series.

OUTPUT should adapt automatically.

Can you help me?

Answer 1

={INPUT1!A1:C1,INPUT2!B1:C1;
 {QUERY({INPUT1!A2:D}, "select Col1,Col2,Col3,' ',Col4 where Col1 is not null label ' '''");
  QUERY({INPUT2!A2:D}, "select Col1,' ','  ',Col2,Col3 where Col1 is not null label ' ''','  '''")}}