比较 Hive QL 中的时间戳和字符串

Question

There is a dataset containing some values that are not desirable: for example, they are missing and shown in '1970/01/01 00:00:00' as the placeholder.

To make sure the query is what I want, how should I filter on this column (timestamp data type)? Or I should put: where does it go wrong if I wrote:

select * from table where timestamp_col <> '1970-01-01 00:00:00'

Answer 1

cast string to timestamp and you will see. In some Hive versions timestamp requires also 0 milliseconds to be added:

select timestamp('1970-01-01 00:00:00.0') 

check that it returns timestamp, not NULL and use in the filter