innerjoin & for all entries

[Former Member]

what is innerjoin & for all entries?

which one is used in which position,explain plzzzzzzzzzzzzzzzzz.

explain advantages & disadvantages?

[Former Member]

hi,

follow these links for knowing the difference between For all entries and joins.

http://www.erpgenie.com/abap/performance.htm#For%20all%20entries

http://blogs.ittoolbox.com/sap/db2/archives/for-all-entries-vs-db2-join-8912

1. INNER JOIN

DBTAB1 <----

---

> DBTAB2

It is used to JOIN two DATABASE tables

having some COMMON fields.

To Impove the perfomance of program you can use for all entries instead of your inner join...This is always preferable..But before make a check and make sure that your internal table is not empty.

2. Whereas

For All Entries,

DBTAB1 <----

---

> ITAB1

is not at all related to two DATABASE tables.

It is related to INTERNAL table.

3. If we want to fetch data

from some DBTABLE1

but we want to fetch

for only some records

which are contained in some internal table,

then we use for alll entries.

*----

---

1. simple example of for all entries.

2. NOTE THAT

In for all entries,

it is NOT necessary to use TWO DBTABLES.

(as against JOIN)

3. use this program (just copy paste)

it will fetch data

from T001

FOR ONLY TWO COMPANIES (as mentioned in itab)

FOR ALL ENTRIES is an effective way of doing away with using JOIN on two tables.

You can check the below code -

SELECT BUKRS BELNR GJAHR AUGDT

FROM BSEG

INTO TABLE I_BSEG

WHERE BUKRS = ....

SELECT BUKRS BELNR BLART BLDAT

FROM BKPF

INTO TABLE I_BKPF

FOR ALL ENTRIES IN I_BSEG

WHERE BUKRS = I_BSEG-BUKRS

AND BELNR = I_BSEG-BELNR

AND BLDAT IN SO_BLDAT

Advantages:

1) For all entries avoids inner join & so the performance increases.

2) For specified values in 1 itab, if you to fetch values from other table you can use it.

3) Use of select stmt in loop is gets avoided, as u can use read statement on the the new itab.

http://www.thespot4sap.com/articles/SAPABAPPerformanceTuning_ForAllEntries.asp