Knex: Implement SKIP LOCKED

[marianomerlo]

Since POSTGRESQL 9.5, there is an SKIP LOCKED option for SELECT FOR SHARE/FOR UPDATE that is extremely helpful.

It would be useful to support this.

Thanks

[officer-rosmarino]

Would be really useful.

The only workaround until now looks like performing a raw query.

knex.raw('select * from table for update skip locked')

[ricmzn]

I also want this, so I've implemented the functionality for PostgreSQL with some unit + integration tests, but I'll hold onto the PR for a few days until I also have it working on MySQL and MariaDB, for completeness. My changes are already on a public fork, however.

[marianomerlo]

Thank you so much for this! Closing issue since you all rock!