Scenario: You're asked to rewrite SQL for UseCase#14 because it's slow. I'd argue the developer find it more quickly if it's stored in a separate .SQL file with

Scenario: You're asked to rewrite SQL for UseCase#14 because it's slow. I'd argue the developer find it more quickly if it's stored in a separate .SQL file with a file name related to the use case (discoverability). It would also separate better in source control history as you'd see when you did SQL changes and when you did PHP changes. Could be valuable when bug-hunting. edit: And the obvious: instead of scrolling to line 762, column 18 of PHP file X, you open file Y on line 1, column 1. It's also an .SQL file, which tells an IDE to syntax highlight it as SQL and not PHP. Yes, there's a performance cost. Hard disks are fast, though. And then there's caching. I always value maintanability higher than performance, as maintainability often is correlated with number of bugs. You suggest to wrap the SQL statement in a function, and that might be just as fine. There's no single best solution here. Just a lot of solutions that are better than the Bitcoin-class ;-)