Combine columns where there is only one data cell per row in Google Sheets

Question

I have Google Sheets data that looks like this:

    A | B | C 
   -----------
1 | a |   |  
2 |   | b | 
3 | c |   |
4 |   |   | d
5 |   | e | 
6 | f |   | 
7 |   |   | g
8 |   | h | 

I need to combine this data into one column like this:

| D |
-----
  a
  b
  c
  d
  e
  f
  g
  h

For every row, there is only one data cell in Columns A, B, or C. Is it possible to do this using a Google Sheets formula?

Thank you all for your help.

Answer 1

Data type : strings

use some concatenation. Try this in D1

=ArrayFormula(A:A&B:B&C:C)

---

Data type : value

If you have number data then include a VALUE() function like so:
=ARRAYFORMULA(VALUE(A:A & B:B & C:C))
Credit to @iandllnghm in the comments of this answer.

Answer 2

We can use the OFFSET function in the following formulas:

+----+----+---+---+-----------------+
|  A |  A | B | C |       D         |
+----+----+---+---+-----------------+
|  1 | a  |   |   | =A1             |
|  2 |    | b |   | =OFFSET($A2,,1) |
|  3 |    |   | c | =A3             |
|  4 |    | d |   | =OFFSET($A4,,2) |
|  5 | e  |   |   | =OFFSET($A5,,1) |
|  6 |    | f |   |                 |
|  7 |    |   | g |                 |
|  8 |    | h |   |                 |
|  9 | i  |   |   |                 |
+----+----+---+---+-----------------+

We place them in the D column starting from cell D1
Since we have a repeating pattern we select and drag down cells D3-D5.