- "SELECT INTO TABLE is better than 'INTO CORRESPONDING FIELDS OF' is a well established myth which is wrong.
- There is an apt document for your reference written by Thomas Zloch in this regard.
Why "INTO CORRESPONDING" is much better than its reputation
- Now about performance tuning, it is a very subjective term. You have to be more specific while asking about performance tuning. I would better give hints about some tcodes which you could make use while analyzing performance such as ST05, SAT etc. You should also not forget about the code checker you are having in SE38. In addition to it have a research on SLIN tcode as well.
Regards,
Philip.