SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 2)
    Function toDecimal64OrNull (alias x) (children 1)
     ExpressionList (children 2)
      Literal \'\'
      Literal UInt64_0
    Function toDecimal64OrNull (alias y) (children 1)
     ExpressionList (children 2)
      Literal \'-0.42\'
      Literal UInt64_3
