query returning empty row

[bharani kumar]

SELECT updateDate,cHospital,cHospital1,cHospital2 FROM med_patient WHERE
cCurstatus!='completed' AND cMmrcashworker = '2' AND
(cHospital = '1234' OR cHospital1 = '1234' OR cHospital2 ='1234') AND
updateDate between '2010-01-01' and '2010-01-28' order by id desc

I have one patient entry,and his  updateDate is 2010-01-17 ,

but my above query return empty row , Why ?


(  Note -->  my updateDate  field is varchar type)



Thanks