0 - 2 of 2 tags for percentile_cont

Any ideas why percentile_cont() will prevent a row from returning when the source rows (the 'group') all contain null values?  I expect to see the row with perhaps NULL in that column.  Teradata Release 14.10.02 Version 14.10.02.08f

In my previous posts on missing functions i covered SQL:2008 DENSE_RANK and CUME_DIST & NTILE.