SQL query analysis

[partiallyordered]

PR #10 makes explicit a behaviour that was previously implicit.

Each of the queries modified in that PR should be evaluated for correctness and modified accordingly. As the functionality we've observed seems correct, it's likely that the queries are working correctly, however we should attempt to eliminate usage of ANY_VALUE by correct usage of GROUP BY, aggregate functions such as SUM, or introduction of explicit one-to-one relationships between the variables in the SELECT clause to prevent or minimise hard-to-debug issues in future.

[KamuelaFranco]

@msk- Do those merges mean this can be closed?

[partiallyordered]

No, not yet, I'm not aware that anyone has actually done a decent analysis of the usage of ANY_VALUE in the db queries. I somewhat expect that all usages thereof should disappear, but I'm a bit hesitant to declare as much.