join into left table

Dear all,

I have two tables:

left: Table A with column Field A1, A2

right: Table B with column Field B1, B2

I join both tables with matching rows, left unmatched rows, key is field A1 to B1

In case of match I would like to fill table A column A2 with value table B column B2

In case of nomatch table A cloumn A2 should left untouched

How to do best way?

Thanks for help!

BR,

Heinz