SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function quantileExactWeighted (children 2)
     ExpressionList (children 2)
      Identifier x
      Identifier y
     ExpressionList (children 1)
      Literal Float64_0.5
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Function CAST (alias x) (children 1)
            ExpressionList (children 2)
             Literal NULL
             Literal \'Nullable(UInt8)\'
           Literal UInt64_1 (alias y)
