[mysql] How do I query between two dates using MySQL?

When using Date and Time values, you must cast the fields as DateTime and not Date. Try :

SELECT * FROM `objects` 
WHERE (CAST(date_field AS DATETIME) 
BETWEEN CAST('2010-09-29 10:15:55' AS DATETIME) AND CAST('2010-01-30 14:15:55' AS DATETIME))