SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier m
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier a
     Literal \'OK\'
   ExpressionList (children 2)
    OrderByElement (children 1)
     Identifier a
    OrderByElement (children 1)
     Identifier f
