using a list to query

I have a list (or array) of primary keys stored in a field (data type text).
I would like to use the list to retrieve all the data from a table based on
the list.

my text field contains:
'123,134,343,345'

I would to do something like the following:

Select * from table1 where table1.pkid in (select myTextfield from table2)

So the question is there a simple way to use the list to retrieve my data?
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John Fabiani