* Fix `LUA_SQL_NULL` leaking into `order by` comparisons
Note: SQL `NULLS LAST` is now default behaviour!
* Fix `objectVariable` unset for empty groups
* Fix non-grouped `having` used wrong environment builder
Note: Queries similar to the following one now works correctly:
```sql
${query[[
from
tags.page
having
name == 'index'
]]}
```
* Fix `generateKey` did not handle `LUA_SQL_NULL`
* Refactor/deduplicate duplicated `order by` comparator
* Add `isSqlNull` helper
Signed-off-by: Matouš Jan Fialka <mjf@mjf.cz>
Matouš Jan Fialka
bc2ae5e46f