ABAP group by 语句学习

第一个案例：原文链接：https://blog.csdn.net/lmf496891416/article/details/111317377

第一步：定义结构，此处定义了三个字段 key1 ,key2 ,col ,然后定义表 itab 参照结构 struct

TYPES: BEGIN OF ty_employee,name TYPE char30,role TYPE char30,age  TYPE i,sex  TYPE char10,END OF ty_employee,
ty_employee_t TYPE STANDARD TABLE OF ty_employee WITH KEY name.

第二步，赋值

DATA(gt_employee) = VALUE ty_employee_t(
( name = 'John'     role = 'ABAP guru'       age = 34  sex =  'MAN'   )
( name = 'Alice'     role = 'FI Consultant'   age = 42  sex =  'WOMAN'  )
( name = 'Barry'    role = 'ABAP guru'       age = 54   sex =  'WOMAN'  )
( name = 'Mary'     role = 'FI Consultant'   age = 37  sex =  'WOMAN' )
( name = 'Arthur'   role = 'ABAP guru'       age = 34  sex =  'MAN'  )
( name = 'Mandy'   role = 'SD Consultant'     age = 64  sex =  'MAN'  ) ).

第三步：loop group by
第一个循环先从第一行 ABAP guru开始，然后可以看到有3个 ABAP guru,所以 SIZE = 3 ,这是第一组，所以 index = 1
然后第二个循环，将组中的数据读出来计算平均年龄，这时候把3个ABAP guru拿出来，计算平均年龄
然后回到第一个循环，从第二行FI Consultant 开始，然后可以看到有2个FI Consultant。所以SIZE = 2 ,这是第二组，所以 index = 2
然后在第二个循环中，将组中的数据读取出来，然后输出
下面同理

LOOP AT gt_employee INTO DATA(ls_employee) GROUP BY ( role  = ls_employee-rolesize  = GROUP SIZE  "分组组数"index = GROUP INDEX ) "分组的组序号"ASCENDING    ASSIGNING FIELD-SYMBOL(<group>).CLEAR: gv_tot_age.WRITE: / | 组序号: { <group>-index }    角色: { <group>-role WIDTH = 15 }|& |     这个组有几条数据: { <group>-size  } |."loop循环组，将组里的数据读出来"LOOP AT GROUP <group> ASSIGNING FIELD-SYMBOL(<ls_member>).gv_tot_age = gv_tot_age + <ls_member>-age.WRITE: /13 <ls_member>-name .ENDLOOP.gv_avg_age = gv_tot_age / <group>-size.WRITE: / |组平均年龄: { gv_avg_age }|.SKIP.
ENDLOOP.