How do I retrieve data in SQL from a previous date in the pass 12 months in a WHERE CLAUSE using the date and time functions?
Both of these should work depending on what you need.

For any date range:

WHERE CLM_FROM_DT BETWEEN '20160331' AND '20170331' 


If you are looking for 1 year back from current date:

WHERE CLM_FROM_DT&gt;DATEADD(year,-1,GETDATE())


If you are looking for 1 year back from specific date (2017-3-31) as per your comment:

WHERE CLM_FROM_DT&gt;DATEADD(year,-1, '20170331')