SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier /t0
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier /t1
     TableJoin (children 1)
      ExpressionList (children 1)
       Identifier a