added joins for RDDs and DataFrames

mahmoudparsian · mahmoudparsian · commit d4a04fd256af · 2022-06-03T15:40:00.000-07:00
diff --git a/code/bonus_chapters/join/python/README.md b/code/bonus_chapters/join/python/README.md
@@ -1 +1,5 @@
-Join in Spark
+# Join in Spark
+
+A JOIN clause is used to combine rows from two tables 
+(expressed as RDDs or DataFrames), based on a related 
+column between them.
