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