PostgreSQL：`row_alias为null`且`row_alias不是null`返回值不一致

我在SQL select中偶然发现了一个奇怪的现象:

select 1
, ui as row_value
, ui is null as "ui is null"
, ui is not null as "ui is not null"
from user_info ui
where ui.user_id = 1003;

此SQL查询的输出: | ？专栏？| UI| UI为null| UI不为空| | ———|———|———|———| | 1|("0000—00—00 00:00:00.00000 + 00"，系统，"0000—00—00 00:00:00.0000000 + 00"，系统，0000，正常，00000FEE，f00d00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000|虚假|虚假|

问题是ui is null和ui is not null列的结果行值都是false，而列row_value包含row本身(不是null).

奇怪的是，我无法设法用内联值来再现它，例如:

-- working as expected
select row(1, 2, 'Hello') as original_row
, row(1, 2, 'Hello') is null as row_is_null
, row(1, 2, 'Hello') is not null as row_is_not_null

甚至不使用虚拟表格:

-- working as expected

create table table_1
(
    table_1_id int not null primary key generated always as identity,
    title      text
);

create table table_2
(
    table_2_id int not null primary key generated always as identity,
    title      text,
    table_1_id int references table_1 on delete cascade
);

create table table_3
(
    table_3_id int not null primary key generated always as identity,
    title      text,
    table_2_id int references table_2 on delete cascade
);

insert into table_1 (title)
values ('Table1 Row 1')
         , ('Table1 Row 2');

insert into table_2 (title, table_1_id)
values ('Table2 Row 1', 1)
         , ('Table2 Row 2', 2);

insert into table_3 (title, table_2_id)
values ('Table3 Row 1', 1)
         , ('Table3 Row 2', 2);

select t1.title
         , t2
         -- , t2 is null
         -- , t2 is not null
         , t3
         , t3 is null
         , t3 is not null
from table_1 t1
    left join public.table_2 t2 using (table_1_id)
    left join public.table_3 t3 on t2.table_2_id = t3.table_2_id and t3.title = 'Table3 Row 1'
where t1.table_1_id = 1
;

这两个最新的代码片段都按预期工作，即x is null返回的值与x is not null相反.

thanks in advance

EDIT:

当使用特定字段的语法时(如ui.user_id is (not) null)，那么问题就消失了.那么，我想问一个问题，这是普遍喜欢的形式，还是我原来的方法也应该工作？(我以前没有直接判断row的问题)