Why the ATC message "DB Operation SELECT for ... found" is a problem ?

I´m analysing the ATC report and have a doubt about the Check Message: "DB Operation SELECT for ... found."

The code is:

" SELECT <columnA> <columnB> FROM <table>

            INTO CORRESPONDING FIELDS OF TABLE <ti_table>

            FOR ALL ENTRIES IN <another_ti_table>

            WHERE <where clause>."

Whats the problem with code above? Why ATC marks it as a problem?

Thanks!