performance tuning

Hi,

I am having this problem with performance that in a particular SELECT query the earlier programmers has used inner join and for all entries. this is affecting the performance very badly.can you please suggest an alternative so that the performance can be improved.

the code goes as

SELECT vbeln

fkart

kunag

bukrs

fksto

INTO CORRESPONDING FIELDS OF TABLE i_common_usrstat1

FROM vbrk

FOR ALL ENTRIES IN i_billtypes

WHERE ( fkart = i_billtypes-adjfkart_1 OR

fkart = i_billtypes-adjfkart_2 OR

fkart = i_billtypes-adjfkart_3 )

AND fkdat = p_date

AND bukrs IN s_bukrs.

IF sy-subrc = 0.

SELECT b~vbeln

b~posnr

b~netwr

b~mwsbp

c~vbelv

c~posnv

c~waers

INTO CORRESPONDING FIELDS OF TABLE i_common_usrstat2

FROM ( vbrp AS b

INNER JOIN vbfa AS c

ON ( c_{vbeln = b}vbeln

AND c_{posnn = b}posnr

AND c~vbtyp_n = c_invty ) )

FOR ALL ENTRIES IN i_common_usrstat1

WHERE b~mandt EQ sy-mandt

AND b~vbeln EQ i_common_usrstat1-vbeln.