1、使用where语句
不推荐
Select * from zflight.
Check : zflight-airln = ‘LF’ and zflight-fligh = ‘BW222’.
Endselect.
推荐
Select * from zflight where airln = ‘LF’ and fligh = ‘BW222’.
Endselect.
2、使用聚合函数
不推荐
Maxnu = 0.
Select * from zflight where airln = ‘LF’ and cntry = ‘IN’.
Check zflight-fligh > maxnu.
Maxnu = zflight-fligh.
Endselect.
推荐
Select max( fligh ) from zflight into maxnu where airln = ‘LF’ and cntry = ‘IN’.
3、使用视图代替基本表查询
不推荐
Select * from zcntry where cntry like ‘IN%’.
Select single * from zflight where cntry = zcntry-cntry and airln = ‘LF’.
Endselect.
推荐
Select * from zcnfl where cntry like ‘IN%’ and airln = ‘LF’.
Endselect.
4、使用INTO table 代替select endselect
不推荐
Refresh: int_fligh.
Select * from zflight into int_fligh.
Append int_fligh. Clear int_fligh.
Endselect.
推荐
Refresh: int_fligh.
Select * from zflight into table int_fligh.
5、使用批量修改内表代替逐行修改
不推荐
Loop at int_fligh.
If int_fligh-flag is initial.
Int_fligh-flag = ‘X’.
Endif.
Modify int_fligh.
Endloop.
推荐
Int_fligh-flag = ‘X’.
Modify int_fligh transporting flag where flag is initial.
6、使用二分法查询，提高查询内表数据速度
不推荐
Read table int_fligh with key airln = ‘LF’.
推荐
Read table int_fligh with key airln = ‘LF’ binary search.
SAP ABAP 性能优化技巧 — 使用二分查找(Binary Search)选项
READ命令使用顺序查找数据表，这会降低处理速度。取而代之，使用binary search的附加命令，可以使用二分查找算法，可以帮助加快内表查找速度。 在使用binary search之前必须首先将内表排序，否则有可能找不到记录，因为二分查找反复将查找区间对半划分，如果要查找的值小于查找区间的中间位置的数据项值，则查找区间将缩小到前半个区间，否则查找将局限于后半区间.
不推荐使用：
Read table int_fligh with key airln = ‘LF’.
推荐使用：
SORT int_fligh by airln.
Read table int_fligh with key airln = ‘LF’ binary search.
应用：
with key
read table itab with key
可以变通的写这条语句。
.........
endloop.
7、两个内表添加使用批量增加代替逐行
不推荐
Loop at int_fligh1.
Append int_fligh1 to int_fligh2.
Endloop.
推荐
Append lines of int_fligh1 to int_fligh2.
8、 使用FOR ALL Entries
不推荐
Loop at int_cntry.
Select single * from zfligh into int_fligh where cntry = int_cntry-cntry.
Append int_fligh.
Endloop.
推荐
Select * from zfligh appending table int_fligh
For all entries in int_cntry
Where cntry = int_cntry-cntry.
9、使用sort by 代替order by
10、避免使用SELECT DISTINCT语句
使用的 ABAP SORT + DELETE ADJACENT DUPLICATES 代替.
11、两个实例
DATA: BEGIN OF it_mara OCCURS 0,
matnr LIKE mara-matnr,
maktx LIKE makt-maktx,
END OF it_mara.
第一种写法:
Select matnr
INTO it_mara
FROM mara.
APPEND it_mara.
ENDSelect.
第二种写法(high performace):
Select matnr
INTO TABLE it_mara
FROM mara.
==========================================
DATA: BEGIN OF it_mara OCCURS 0,
matnr LIKE mara-matnr,
maktx LIKE makt-maktx,
END OF it_mara.
DATA: BEGIN OF it_makt OCCURS 0,
matnr LIKE mara-matnr,
maktx LIKE makt-maktx,
END OF it_makt.
第一种写法:
LOOP AT it_mara.
Select SINGLE maktx
INTO it_mara-maktx
FROM makt
Where matnr = it_mara-matnr AND
spras = sy-langu.
MODIFY it_mara TRANSPORTING maktx.
ENDLOOP.
第二种写法(high performace)
Select matnr maktx
INTO TABLE it_makt
FROM makt
FOR ALL ENTRIES IN it_mara
Where matnr = it_mara-matnr and
spras = sy-langu.
=========================================
1 数据——>工作区，工作区——>内表，
2 数据——>内表
很明显少了一个过程 效率自然高了 如果数据量越大,效果是可想而知的
