Inherited from Add
Inherited from Serializable
Inherited from Serializable
Inherited from NullIntolerant
Inherited from BinaryArithmetic
Inherited from BinaryOperator
Inherited from ExpectsInputTypes
Inherited from BinaryExpression
Inherited from Expression
Inherited from TreeNode[Expression]
Inherited from Product
Inherited from Equals
Inherited from AnyRef
Inherited from Any
Unlike the "Add" operator that follows SQL semantics of returning null if either of the expressions is, this will return the non-null value if either is null or add if both are non-null (like the "sum" aggregate).