I want to know how to update a table in MS Access with the data from
another table, matching on a field which is NOT the primary key (but
is unique).

e.g. the table structure is as follows;

Table1: (table to be updated TO)
field_x field_y Field_z

Table2: (table to be appended FROM)
field_y field_z

field_x is the primary key, I want the solution to match on field_y,
then copy the data in Table2.field_z to Table1.field_z (currently
blank)

I'm sure this is really simple but cannot fo the life of me figure it out!

Thanks