Fetch record based on last modified time in zoho crm

Fetch record based on last modified time in zoho crm

Hi

I have created a script in php in which I get Account name from zoho and store in database. I have created one more field last_modified_time in database. It will keep current time stamp by default. It is updated automatically when any action is performed on database.

I want to get only data from zoho whose modified time is greater than last_modified_time in database.
So I used  last Modified Time function to fetch the data but it is not working for me.
In php, I have created a function getdatafromzoho() which get All the data from zoho Account module.
I want to get only modified data not whole data. So I have used below URL by putting last modified Time condition,but it is no working. If I remove last modified time condition from the URL, then it is working fine.

https://crm.zoho.com/crm/private/xml/Accounts/getRecords?authtoken=xxxx&scope=crmapi&newFormat=1
&selectColumns=Accounts(Account Name)
&lastModifiedTime=2015-11-17 15:38:24
&fromIndex=1
&toIndex=25

Please tell me how can I get only the data whose lastmodifiedTime is greater than specified time.