空与“”问题？？

create table TABLE_NAME(column_name Nullable(String)) Engine=Log;
insert into TABLE_NAME values(''), ('1'), (Null);

SELECT *
FROM TABLE_NAME

┌─column_name─┐
│             │
│ 1           │
│ ᴺᵁᴸᴸ        │
└─────────────┘

SELECT COUNT()
FROM TABLE_NAME
WHERE isNull(column_name)

┌─COUNT()─┐
│       1 │
└─────────┘

SELECT COUNT()
FROM TABLE_NAME
WHERE column_name = ''

┌─COUNT()─┐
│       1 │
└─────────┘

SELECT COUNT()
FROM TABLE_NAME
WHERE coalesce(column_name, '') = ''

┌─COUNT()─┐
│       2 │
└─────────┘