How to select some date objects from a dataset which contains some values?

[zhenyuzeng]

Hello,
I have a data set which contains a date column that contains some values and data objects. I need to select some data objects but the values in that column stop me do that. For example:

test = Dataset[{<|"a" -> 2, "b" -> DateObject[{2022, 2}]|>, <|
    "a" -> 2, "b" -> DateObject[{2022, 2}]|>, <|"a" -> 2, "b" -> 0|>}]
test[Select[#"b" <= DateObject[{2022, 5}] &], All]

How should I select data objects in this case?

[gdelfino (Gustavo Delfino)]

How about this way:

test[Select[DateObjectQ[#b] && #b <= DateObject[{2022, 5}] &], All]

[zhenyuzeng]

Yes! Thanks a lot.