Added example to remove duplicated rows by columns

Author: NithinRamuSAS

By Syntax/SORT Procedure/6_Remove duplicated rows by columns.sas

@@ -0,0 +1,49 @@
+/************************************************************************************************
+ REMOVE DUPLICATED ROWS by COLUMNS
+     This program sort the input table by specified columns to ensure rows with same values in
+         these columns are adjacent. Furthermore, the sorting ensures that the first record in
+         the group has the highest value based on a column. Then, all subsequent (or duplicate)
+         rows based on specified columns are removed.
+     Keywords: PROC SORT, remove duplicates
+     SAS Versions: SAS 9, SAS Viya
+     Documentation: https://documentation.sas.com/?cdcId=pgmsascdc&cdcVersion=default&docsetId=proc&docsetTarget=p1nd17xr6wof4sn19zkmid81p926.htm
+     1. Create the WORK.CLASSTEST table and print it.
+     2. PROC SORT sorts rows by specified columns (here: Name) so that duplicated
+        rows will be sequential, and the first record in the group has the highest value for a
+        given column (here: Score).
+     3. Another PROC SORT step with the NODUPKEY option deletes rows with duplicate BY values
+        by the specified columns (here: Name), thus leaving only one row (here:the one with the
+        highest Score for each Name).
+************************************************************************************************/
+
+
+data classtest;                                                       /*1*/
+   infile datalines dsd;
+   input
+      Name :$7.
+      Subject :$7.
+      Score;
+datalines4;
+Judy,Reading,91
+Judy,Math,79
+Barbara,Math,90
+Barbara,Reading,86
+Louise,Math,72
+Louise,Reading,65
+William,Math,61
+William,Reading,71
+Henry,Math,62
+Henry,Reading,75
+Henry,Reading,84
+Jane,Math,94
+Jane,Reading,96
+;;;;
+run;
+
+proc sort data=classtest out=classtest_sort;                         /*2*/
+    by Name descending Score;
+run;
+
+proc sort data=classtest_sort out=classtest_nodup nodupkey;          /*3*/
+    by Name;
+run;