Judgment of PostgreSQL null value

Null value judgment

-- 查询为空的 is null,sql简写isnull
select * from employees where manager_id isnull;

select * from employees where manager_id is null;

non-null judgment

-- 查询不为空的 is not null;sql简写notnull
select * from employees where manager_id is not null;
select * from employees where manager_id notnull;

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