Export by date of input in ODK collect

I am currently working on a project where we are using the same question to various groups and in different days. We would like to sort out the information by the date of input in the ODK collect system (so we know which group was interviewed).

So we tried to do our first export but the information was mixed and now we are struggling to know which group is which. Is there a way where we can to so? Have the exports be by dates? OR anything else to make the data sorting more friendly?

Also realised that on one of the form exported not all the information was transferred.

I hope that I made myself clear as I was finding it hard to find the right words to explain my issue.

Typically, if date of input is important it is included as part of the form design. There are several different metadata types that can be gathered as described at http://xlsform.org/#metadata

Since it sounds like you've already collected your data, you can use ODK Briefcase to pull down your data locally and then either export a date range or export all of your data with a submission date field. Download the latest Briefcase at https://opendatakit.org/downloads/download-info/odk-briefcase/ and read about using it at http://docs.opendatakit.org/briefcase-guide/.