Cast type int2vector/array_field to character

Forgiveness if have been asked previously.

Simple question:
1. How can I cast type int2vector/array_field into character?
2. My case like this: I have 2 table,
first table: 

Field1 Field2
====== ======
1      aaaaa
2      bbbbb
3      ccccc
4      ddddd
5      eeeee

second table: (only one field)

Array_Integer
=============
1 2 4

Wishing to be yielded from relationship both of that:

Result
======
aaaaa
bbbbb
ddddd

How command of SQL to get that result?

exist in my mind now: "select * from table1 where field1 in (select
Array_Integer from table2". :)

Thanks in advance,
Fadjar Hamidi