The document discusses using Arel to construct ActiveRecord queries in a more object-oriented way compared to using literal SQL strings. It provides examples of using Arel to select columns, join tables, and add where conditions in a chained method syntax. Some benefits highlighted are that Arel avoids needing to know SQL syntax, provides Ruby syntax checking, and results in more readable queries.
![Advanced Arel: When ActiveRecord Just Isn't Enough](https://cdn-ak-scissors.b.st-hatena.com/image/square/8472a868a4821b322b728a9a1417bf6f536c49ce/height=288;version=1;width=512/https%3A%2F%2Fcdn.slidesharecdn.com%2Fss_thumbnails%2Farel-140423113724-phpapp01-thumbnail.jpg%3Fwidth%3D640%26height%3D640%26fit%3Dbounds)