When trying to use sqlc for our project I noticed a few things were not supported that we require. We do use CockroachDB with the postgres engine.

1. The ON UPDATE expression caused SQL validation errors. This is specific to CRDB.
2. Hash sharded indexes caused SQL validation errors as well
3. Composite primary keys with ordering like PRIMARY KEY(col1, col2 DESC) said that DESC was an error
4. The STORING clause was also found to be an error