Where clause fails if using same date in a “greater than or equal to” and a “less than or equal to”

Question

Why does this query not return any rows when date1 , date2 , and dateField are the same and there are rows where dateField == date1 that should be returned?

Examples:

select * from tableName where dateField >= date1 and dateField <= date2

Answer 1

It appears that the time part of the smalldatetime field dateField used to be all zeros, and now it's not. The solution was to just compare the date portion of dateField .

SELECT * 
FROM tableName
WHERE 
CONVERT(DATE, dateField) >= date1 AND CONVERT(DATE, dateField) <= date2