CreateFunctionQuery oldest_before (children 2)
 Identifier oldest_before
 Function lambda (children 1)
  ExpressionList (children 2)
   Function tuple (children 1)
    ExpressionList (children 1)
     Identifier age_max
   Subquery (children 1)
    SelectWithUnionQuery (children 1)
     ExpressionList (children 1)
      SelectQuery (children 5)
       ExpressionList (children 1)
        Identifier uid
       TablesInSelectQuery (children 1)
        TablesInSelectQueryElement (children 1)
         TableExpression (children 1)
          TableIdentifier users
       Function less (children 1)
        ExpressionList (children 2)
         Identifier users.age
         Identifier age_max
       ExpressionList (children 1)
        OrderByElement (children 1)
         Identifier users.age
       Literal UInt64_1
