Describe UNION's cast on derived table - Mailing list pgsql-docs

From PG Doc comments form
Subject Describe UNION's cast on derived table
Date
Msg-id 20180109130542.21782.91514@wrigleys.postgresql.org
Whole thread Raw
List pgsql-docs
The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/10/static/typeconv-union-case.html
Description:

Hi!

Whilst the type conversion works great on the query ;select 10 as col1 union
select null as col1;, it does not on the almost same one ;select col1 from
(select 10 as col1) t1 union select col1 from (select null as col1) t2;,
giving the error "UNION types integer and text cannot be matched". I'm using
a 64-bit PostgreSQL 10.1 on linux.

Please, describe this situation better on the docs. Thank you so much.

pgsql-docs by date:

Previous
From: "Brian McKiernan"
Date:
Subject: Advice on Contiguous IDs
Next
From: Alvaro Herrera
Date:
Subject: Re: Advice on Contiguous IDs