SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Identifier a (alias test2.a)
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier test1
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier test2
     TableJoin
