Google Sheets, Array Formula to merge 2 Sheets into one, and append a new column to specify which sheet the data came from

Question

I am trying to merge Sheet1 & Sheet2 into Sheet3. On Sheet3 I would like Column A to display which Sheet the data came from.

Sheet1 (Source #1)

A	B
John Doe	123 Street

Sheet2 (Source #2)

A	B
Jane Smith	999 Street

Sheet3 - Expected results using the formulas below.

A	B	C
Sheet1	John Doe	123 Street
Sheet2	Jane Smith	999 Street

I have tried the following formulas.

=ARRAYFORMULA(
  {
    {"Sheet1",FILTER('Sheet1'!A1:B,'Sheet1'!A1:A<>"")};
    {"Sheet2",FILTER('Sheet2'!A1:B,'Sheet1'!A1:A<>"")}
  }
)

=ARRAYFORMULA(
  {
    {"Sheet1",QUERY('Sheet1'!A1:B,"SELECT * WHERE A is not null")};
    {"Sheet2",QUERY('Sheet2'!A1:B,"SELECT * WHERE A is not null")}
  }
)

Both give the error: In ARRAY_LITERAL, an Array Literal was missing values for one or more rows.

What am I doing wrong? Thanks!

Answer 1

Try:

={QUERY(Sheet1!A:B; "select 'Sheet1',A,B label 'Sheet1'''"; ); 
  QUERY(Sheet2!A:B; "select 'Sheet2',A,B label 'Sheet2'''"; )}