SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Identifier b
    Identifier d
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t1
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier t2
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier a
        Identifier c