Is there a difference between CTRL+D and CTRL+" (quotation marks)

[AKMMS]

And if there is a difference, what is it?

They both appear to copy the data from the cell above the selected cell.

 

[Gary Brown]

Ctrl+D is a relative copy
Ctrl+" is an absolute copy

Example:
Assume...
A1 = +B1
B1 = "Hello"

if you put your cursor in A2 and select Ctrl+D, A2 will be =+B2
if you put your cursor in A2 and select Ctrl+", A2 will be =+B1

 

[Bernard Liengme]

If D1 has a non-formula (text, number, date, TRUE/FALSE) and I use either
CTRL+D or CTRL+" in cell D2 I will get a copy of the value in D1

If D1 has a formula
--
Bernard Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme, the two give a different answer
If D1 has =A1, the in D1 the use of CTRL+D give =A2 which is what I would
get by dragging or copying D1 to D2
But CTRL+" will give =A1 ; so it gives an exact copy of what is in D1
without updating the cell references

best wishes