CreateQuery xxxx_null (children 3)
 Identifier xxxx_null
 Columns definition (children 1)
  ExpressionList (children 1)
   ColumnDeclaration ts (children 1)
    DataType Nullable (children 1)
     ExpressionList (children 1)
      DataType DateTime
 Storage definition (children 3)
  Function MergeTree
  Function toStartOfHour (children 1)
   ExpressionList (children 1)
    Identifier ts
  Set
