How to display dynamic range of data from another sheet, but while transforming one column

Question

I have a sheet of data in the form:

Date           Val
2015-08-05     10
2015-08-09     13
2015-08-14     4

I am trying to display this data in other cell such that it looks like this:

Date           Val
2015-08        10
2015-08        13
2015-08         4

I do not want to use a text() function that transforms yyyy-mm-dd to yyyy-mm and then drag that down column A. I want all of the data to be dynamically populated such that adding new columns to the source sheet causes the other sheet to update automatically.

How can I do this?

Answer 1

It appears you don't need to change the data at all, just change the presentation of the data, i.e., formatting. Select column A, go to Format -> Number -> More formats -> More data and time formats, and set the desired format there:

New date/time data added to Column A will automatically be shown as above.

Answer 2

Seems OP was happy with response from Kishan:

=query('source data'!A2:B,"select A,B format A 'yyyy-mm'",0)