SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function equals (children 1)
     ExpressionList (children 2)
      Identifier value
      Literal \'direct,hash\'
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.settings
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier name
     Literal \'join_algorithm\'
