SQL: SELECT with “superpowers”

We all use the SELECT statement daily to retrieve data from the database. SELECT is therefore generally considered a “passive” statement, which simply returns results without modifying anything. But with a small addition, even an ordinary SELECT can turn into an “active” action, able to act on the database but also on the system! The secret lies in the coupling between SELECT and the well-known QCMDEXC procedure, which allows you to execute a CL command, starting from versions 7.4 TR4 and 7.3 TR10 it is also supplied as a scalar function. QCMDEXC can therefore be invoked by any SQL query. Let’s see a practical example right away: the mass rename of a bunch of IFS files. …