diff --git a/docs/sql-programming-guide.md b/docs/sql-programming-guide.md
index 3ca6cc95bd2db25307afb8a827d487fde666e022..0c743c9d6010d9662be04abe1f7da760240d57c4 100644
--- a/docs/sql-programming-guide.md
+++ b/docs/sql-programming-guide.md
@@ -114,6 +114,8 @@ val sqlContext = new org.apache.spark.sql.SQLContext(sc)
 import sqlContext._
 
 // Define the schema using a case class.
+// Note: Case classes in Scala 2.10 can support only up to 22 fields. To work around this limit, 
+// you can use custom classes that implement the Product interface.
 case class Person(name: String, age: Int)
 
 // Create an RDD of Person objects and register it as a table.