SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Identifier table1.a (alias t1_a)
    Identifier table3.a (alias t3_a)
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t1 (alias table1)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier t3 (alias table3)
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier t1_a
        Identifier t3_a
