Previously if the `reverse` named arg was unset (value of NULL), then
SQL would order by NULL instead of ID causing undifined ordering of the
returned rows. To fix that we check for NULL and also make sure to set
the `reverse` arg in the code explicitly as it in the generated code it
is an `interface{}` instead of `bool`.
This commit attempts to fix some issues with the invoice store's schema that we
couldn't foresee before the implementation was finished. This is safe as the
schema has not been instantiated yet outside of unit tests. Furthermore the
commit updates invoice store SQL queries according to fixes in the schema as
well as to prepare the higher level implementation in the upcoming commits.
Set of queries to deal with invoices. A couple of things to take into
account:
- Because the queries are not rewritten at runtime, we cannot have a
generic `INSERT` with different tuples.
- Because the queries are not rewritten at runtime, we cannot build
one query with only the filters that matter for that queries. The
two options are a combinatorial approach (a new query for every
permutation) or a generic query using the pattern
```
SELECT *
FROM table
WHERE (
-- Can be read as:
-- Match the filter 1 value if filter_1 != nil
column_1 >= sqlc.narg('filter_1') OR
sqlc.narg('filter_1') IS NULL
) AND (
column_2 >= sqlc.narg('filter_2') OR
sqlc.narg('filter_2') IS NULL
) ...
```
