>But this would change all records in myval<7. Might not be intended.
Premature optimization...
It is neither the fastest nor the most correct (depending on the unknown purpose). It is not correct for what you pointed out: it might not be intended; and it is not the fastest for if you absolutely know that only the current record might need to be updated, then using a FOR will be slower. In short, it might be the fastest and most correct way for some scenarios, not for all. (and then there might be an argument that UPDATE - SQL might be better than this)
"The five senses obstruct or deform the apprehension of reality."
Jorge L. Borges?
"Premature optimization is the root of all evil in programming."
Donald Knuth, repeating C. A. R. Hoare
"To die for a religion is easier than to live it absolutely"
Jorge L. Borges
