SELECT while MODIFYING existing rows

Hello,

I have an internal table with material, plant, PSS status and some other fields that is already full of data. I want to select the material description from MAKT using the entries in this table and modifying this table at the same time:

SELECT maktx FROM makt INTO CORRESPONDING FIELDS OF TABLE itab

FOR ALL ENTRIES IN itab

WHERE matnr = itab-matnr.

However, this deletes the current entries.

I also tried to use SELECT .... APPENDING INTO CORRESPONDING FIELDS OF TABLE

but am unsure if I am doing it correctly or if there is a different way to do it because the way I have written it, it adds additional rows to my table.

I am aware I can create a separate internal table and then loop through it to modify itab but was trying to see if there is a more efficient way to do this.

Thank you!