How to fetch data from 2 tables

Question

Hi Experts,
I am using 2 Ztables.Let us assume that there are 2 fields in Table1 as a and b and 2nd Table contain c as field.I want to retrive data from these tables by combining the fields of Table1 with that of 2.
Eg: I want to compare a+b with c and fetch records.
Is there any logic to combine 2 fields and compare with 3rd field using a single select statement?
Regds,
Sam.

Answer 1

Hi Sam,
if the tables have one or more common key fields, you can use a JOIN condition for the tables, i.e.
data:
begin of ls_target,
  a like ztable1-a,
  b like ztable1-b,
  c like ztable2-c,
end of ls_target,
lt_target like table of  ls_target.
select ztable1~a ztable1~b ztable2~c
  into corresponding fields of table lt_target
  from ztable1
  join ztable2 ON  ztable2~key = ztable1~key
  where <your condition>.
Note ahead:
1)  some people say select into corresponding fields is not good for performance. I think it is good to avoid errors and nobody ever gave a perfomance proof.
2) Most developers always use an alias such as ztable1AS a, ztable2 AS b. This is due to the fact that after table joins were introduced with release 3.1, the ABAP sample programs an documentation always used the ALIAS clause although it is not necessary nor does it establish transparency.
Kind regards
Clemens