> [!METADATA]+ > **Type**:: [[Conference Talk]] > **Conference**:: [[Sin City Ruby 2022]] > **Authors**:: [[@Colleen]] > **Links**:: ## Notes - [[@Colleen]] - @leenyburger - Software Social Podcast - Hammerstone Podcast - [Simple File Upload](https://simplefileupload.com) - You can send subqueries into a `where` clause - [[Arel]] is the magic sauce behind [[ActiveRecord]] and an [[AST]] - Chainable and composable - Define [[Arel]] tables - `contacts = Contact.arel_table` - `contacts[:email].does_not_match(”%gmail%”)` - `contacts[:created_at].lteq(date)` - `Arel::Predications.instance_methods` - Relational algebra - Common Table Expression (CTE) is the result set of a query and only used in the context of a larger query