Unexpected Results Using NULLIF with VARCHAR

[suyZhong]

CrateDB version

CrateDB 5.6.0-SNAPSHOT built 5ff277c

CrateDB setup information

Manual build following the instructions here: https://github.com/crate/crate/blob/master/devs/docs/basics.rst

Problem description

The third SELECT returns one row (null), which is surprising, given that the result of second query is null. The value of the NULLI((t0.c1), NULL)) expression is null, and thus the third query should return empty.

Steps to Reproduce

DROP TABLE IF EXISTS t0;

CREATE TABLE t0( c1 VARCHAR(500));
INSERT INTO t0 (c1) VALUES (NULL);
REFRESH TABLE t0;

SELECT * FROM t0; -- null
SELECT (NOT NULLIF((t0.c1), NULL)) FROM t0; -- null
SELECT * FROM t0 WHERE (NOT NULLIF((t0.c1), NULL));
-- Expected: empty result
-- Actual:   null

Actual Result

NULL

Expected Result

Empty

[matriv]

This is a bug only on current master, tested with 5.5.2 and a correct result (empty) is returned.

[matriv]

@suyZhong Thx a lot for reporting the issue, it was applicable only for master and it has been fixed.