doc: Clarify status of SELECT INTO on reference page

petere · petere · commit 65330622441d · 2021-01-30T11:21:32.000+01:00
The documentation as well as source code comments weren't entirely clear whether SELECT INTO was truly deprecated (thus in theory destined to be removed eventually), or just a less recommended variant. After discussion, it appears that other implementations also use SELECT INTO in direct SQL in a way similar to PostgreSQL, so it seems worth keeping it for compatibility. Update the language in the documentation to that effect. Discussion: https://www.postgresql.org/message-id/flat/96dc0df3-e13a-a85d-d045-d6e2c85218da%40enterprisedb.com
diff --git a/doc/src/sgml/ref/select_into.sgml b/doc/src/sgml/ref/select_into.sgml
@@ -138,9 +138,11 @@ SELECT * INTO films_recent FROM films WHERE date_prod &gt;= '2002-01-01';
    in <application>ECPG</application> (see <xref linkend="ecpg"/>) and
    <application>PL/pgSQL</application> (see <xref linkend="plpgsql"/>).
    The <productname>PostgreSQL</productname> usage of <command>SELECT
-   INTO</command> to represent table creation is historical.  It is
-   best to use <command>CREATE TABLE AS</command> for this purpose in
-   new code.
+   INTO</command> to represent table creation is historical.  Some other SQL
+   implementations also use <command>SELECT INTO</command> in this way (but
+   most SQL implementations support <command>CREATE TABLE AS</command>
+   instead).  Apart from such compatibility considerations, it is best to use
+   <command>CREATE TABLE AS</command> for this purpose in new code.
   </para>
  </refsect1>
 
