SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Identifier name
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.settings
   Function less (children 1)
    ExpressionList (children 2)
     Function length (children 1)
      ExpressionList (children 1)
       Identifier description
     Literal UInt64_10
