sql: CHAR behavior inconsistent with Postgres

[mgartner]

In Postgres:

marcus=# CREATE TABLE t (c CHAR);
CREATE TABLE

marcus=# INSERT INTO t VALUES (' '), ('');
INSERT 0 2

marcus=# SELECT c = ' ', c = '' FROM t;
 ?column? | ?column?
----------+----------
 t        | t
 t        | t
(2 rows)

In cockroach v21.1.7:

defaultdb> CREATE TABLE t (c CHAR);
CREATE TABLE

defaultdb> INSERT INTO t VALUES (' '), ('');
INSERT 2

defaultdb> SELECT c = ' ', c = '' FROM t;
  ?column? | ?column?
-----------+-----------
   false   |   true
   false   |   true
(2 rows)

Jira issue: CRDB-9714

[rafiss]

More fun behavior on this:

rafiss@127:postgres> select length(c) from t where c = '';
+--------+
| length |
|--------|
| 0      |
| 0      |
+--------+
SELECT 2
Time: 0.008s
rafiss@127:postgres> select length(c) from t where c = ' ';
+--------+
| length |
|--------|
| 0      |
| 0      |
+--------+