1 files changed, 4 insertions, 0 deletions
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/Covariance.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/Covariance.scala
index c175a8c4c7..d80afbebf7 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/Covariance.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/Covariance.scala
@@ -76,6 +76,8 @@ abstract class Covariance(x: Expression, y: Expression) extends DeclarativeAggre
   }
 }
 
+@ExpressionDescription(
+  usage = "_FUNC_(x,y) - Returns the population covariance of a set of number pairs.")
 case class CovPopulation(left: Expression, right: Expression) extends Covariance(left, right) {
   override val evaluateExpression: Expression = {
     If(n === Literal(0.0), Literal.create(null, DoubleType),
@@ -85,6 +87,8 @@ case class CovPopulation(left: Expression, right: Expression) extends Covariance
 }
 
 
+@ExpressionDescription(
+  usage = "_FUNC_(x,y) - Returns the sample covariance of a set of number pairs.")
 case class CovSample(left: Expression, right: Expression) extends Covariance(left, right) {
   override val evaluateExpression: Expression = {
     If(n === Literal(0.0), Literal.create(null, DoubleType),