Unexpected result when using `CONCAT_WS` containing `NULL`

[suyZhong]

CrateDB version

CrateDB 5.7.0-SNAPSHOT built 93ee46e

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 an empty result, which is surprising, given that the result of second query is TRUE. The value of the expression should be TRUE, and thus the third query should return an empty result.

Steps to Reproduce

DROP TABLE IF EXISTS t1;
CREATE TABLE t1(c1 BOOLEAN);
INSERT INTO t1 (c1) VALUES (null);
REFRESH TABLE t1;


SELECT * FROM t1; -- NULL
SELECT (NOT (NOT CONCAT_WS(true, CAST(t1.c1 AS BOOLEAN), true))) FROM t1; -- TRUE
SELECT * FROM t1 WHERE (NOT (NOT CONCAT_WS(true, CAST(t1.c1 AS BOOLEAN), true)));
-- Expected: NULL
-- Actual:   empty result

-- For reference:
SELECT CAST(t1.c1 AS BOOLEAN) FROM t1; -- NULL
SELECT (NOT (NOT CONCAT_WS(true, NULL, true))) FROM t1; -- TRUE
SELECT * FROM t1 WHERE (NOT (NOT CONCAT_WS(true, null, true))); -- NULL

Actual Result

Empty

Expected Result

NULL

[BaurzhanSakhariev]

Thanks for reporting!

This looks like a regression, query works as expected on 5.5.2 and 5.5.3