Maximum number of records for usage of "For all entries"

Question

Hi,
Is there a limit on maximum number of records to be selected from the database using "For all entries"  statement ?
Thanks in advance

Answer 1

There is a UNDOCUMENTED(??) behaviousr
FOR ALL ENTRIES does ahidden SELECT DISTINCT & drops duplicates.
http://web.mit.edu/fss/dev/abap_review_check_list.htm
3 pitfalls
"FOR ALL ENTRIES IN..." (outer join) are very fast but keep in the mind the special features and 3 pitfalls of using it.
(a) Duplicates are removed from the answer set as if you had specified "SELECT DISTINCT"... So unless you intend for duplicates to be deleted include the unique key of the detail line items in your select statement. In the data dictionary (SE11) the fields belonging to the unique key are marked with an "X" in the key column.
^^!!!!
(b) If the "one" table (the table that appears in the clause FOR ALL ENTRIES IN) is empty, all rows in the "many" table (the table that appears in the SELECT INTO clause ) are selected. Therefore make sure you check that the "one" table has rows before issuing a select with the "FOR ALL ENTRIES IN..." clause.
(c) If the 'one' table (the table that appears in the clause FOR ALL ENTRIES IN) is very large there is performance degradation Steven Buttiglieri created sample code to illustrate this.