Re: getting column names

["David G. Johnston" <david.g.johnston@xxxxxxxxx>]

On Tue, Apr 4, 2017 at 2:51 PM, Armand Pirvu (home) <armand.pirvu@xxxxxxxxx> wrote:

But if I join back to foo1 like below I get

select a.audit_id, a.table_name, b[1],b[2]
from
foo1 a,
(select
array(
select
column_name::text from
information_schema.columns
where
table_name=a.table_name
and
(
column_name like '%add_by%'
or
column_name like '%add_date%'
)) b) as foo
;

ERROR:  invalid reference to FROM-clause entry for table "a"
LINE 10: table_name=a.table_name
                    ^
HINT:  There is an entry for table "a", but it cannot be referenced from this part of the query.

​​https://www.postgresql.org/docs/9.6/static/sql-select.html​

​

​Adding LATERAL before the second "from_item" should get rid of the error - whether it results in a working and/or correct query I don't know.​

David J.