What do you mean by NODUP and NODUPKEY options and write difference be

What do you mean by NODUP and NODUPKEY options and write difference between them?

Answer»

PROC SORT in SAS enables the removal of duplicate values from a table primarily by utilizing TWO options:

NODUP VS NODUPKEY -

NODUP	NODUPKEY
Each variable in the data SET can be compared with it.	NODUPKEY only compares the variables that are listed in the BY statement.
NODUP removes duplicate observations where the same values are repeated across all variables.	When NODUPKEY is selected, the duplicate observations are removed where the values of a variable listed in the BY statement are the same.
Syntax: PROC SORT DATA=readin NODUP; By varname; run;	Syntax: PROC SORT DATA=readin NODUPKEY; By varname; run;