Returns the partition number into which a set of partitioning column values would be mapped for any specified partition function.
Syntax
[ database_name. ] $PARTITION.partition_function_name(expression)
It returns a Partition number of column value when mapped to a partition function
this will be useful if you want find the rows in a particular partition
so lets explain this with a simple example
create partition function
now lets create a partitioned table
insert some sample data
now lets see some examples on $partition function