SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function arrayJoin (alias arrayIdx) (children 1)
     ExpressionList (children 1)
      Literal Array_[UInt64_0, UInt64_1]
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier testtable
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier arrayIdx
     Literal UInt64_0