Oracle Compatibility: SELECT IF (...) INTO variable FROM DUAL result in syntax error

Build tested: Github source

/root/columnstore/mariadb-columnstore-server
commit 7db44a78066cb55b7e2ffded80e2673d16940cee
Author: Andrew Hutchings <andrew@linuxjedi.co.uk>
Date: Mon Sep 10 13:39:42 2018 +0100

Revert "MDEV-11036 Add link wsrep_sst_rsync_wan -> wsrep_sst_rsync"

This reverts commit e8a2a751212a04e835b2b03408132ecbbab52410.

/root/columnstore/mariadb-columnstore-server/mariadb-columnstore-engine
commit 3326be00de5f53ec365910f07a7fd882ba193d4d
Merge: ebbeb30 5cab6c4
Author: Andrew Hutchings <andrew@linuxjedi.co.uk>
Date: Tue Sep 18 13:57:17 2018 +0100

Merge pull request #565 from drrtuy/MCOL-1601

MCOL-1601 GROUP BY now supports subqueries in HAVING.

Testing Oracle compatibility feature, using MariaDB 10.3.9 as the reference. SQLMODE has to set as the following:

SET SQL_MODE=ORACLE;

The following query works in MariaDB 10.3.9, but resulted in syntax error in ColumnStore.

SELECT IF (SUBSTR(@msgText, -8) = '\'t exist',1, 0) INTO @expVal from DUAL;

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'INTO @expVal from DUAL' at line 1

The query would work if I remove the "INTO @EXPVAL" part.

I have used "INTO variable" in simpler form queries in many test cases and they worked fine.