Webform get all submission for a node by date
It seems it's not possible directly. See webform_get_submissions date range filter issue.

From taht issue: 


  We now have built-in range functionality in #1237660: Add date range
  or "last X submissions" to CSV/Excel download. That patch just uses
  the existing ability of webform_get_submissions() to filter by SIDs,
  which would probably work in your situation too as long as you can
  retrieve a list of SIDs by date.


So you have to build a query to retrieve a list of SID's bty date and then pass it to webform_get_submissions.