rspec/rules/S1494/abap/rule.adoc

== Why is this an issue?

``++JOIN++`` bypasses the SAP table buffer. Buffered tables should be accessed with the simplest ``++SELECT++`` statements possible so as not to risk bypassing the buffer.

If one of the tables in a ``++JOIN++`` is buffered, it would be an advantage to first import the required entries using a ``++SELECT++`` into an internal table ``++itab++``, and then for example, using the statement ``++SELECT ... FOR ALL ENTRIES IN itab++`` to access further tables.


=== Noncompliant code example

For ``++JOIN++`` clauses:

[source,abap]
----
SELECT s~carrid s~carrname p~connid
       INTO CORRESPONDING FIELDS OF TABLE itab
       FROM scarr AS s
       LEFT OUTER JOIN spfli AS p ON s~carrid   =  p~carrid
            AND p~cityfrom = p_cityfr.
----

For subqueries

[source,abap]
----
SELECT  carrname
  INTO  TABLE name_tab
  FROM  scarr
  WHERE EXISTS ( select  *
                   FROM  spfli
                   WHERE carrid   =  scarr~carrid AND
                         cityfrom = 'NEW YORK'        ).
----


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Make sure this use of  a "JOIN" clause is strongly indicated.

Make sure this use of a subquery is strongly indicated.


endif::env-github,rspecator-view[]