I'm having trouble with using the between operator in where clause. I have the following queries:

SELECT * 
FROM table
WHERE timestamp_column BETWEEN (current_date - interval '1 day')::date 
                           AND current_date   => 500k rows
SELECT *
FROM table
WHERE timestamp_column >= (current_date - interval '1 day')::date => 1 mil rows

Does anyone have any idea why the result set is different? Shouldn't it be the same? I am trying to compare the number of rows from a database in PostgreSQL with data from Sybase ASE. The same 2 queries ran in Sybase give the same results. The expected result set is 1 milion rows. This should be the number of rows that I have between yesterday and today.

PostgreSQL v9.5, timestamp_column = timestamp without time zone

I tried using now(), current_timestamp but same result.

What am I missing here? If I didn't made myself clear let me know.