Using Arel to Compose SQL Queries

Rails gives us a great DSL for constructing most queries. With its knowledge of the relationships between our tables, it’s able to construct join clauses with nothing more than the name of a table. It even aliases your tables automatically! The method we most often reach for when querying the database is the where method. 80% of the time, your query will only be checking equality, which is what wh

[kitokitoki]

where(foo: ['bar', 'baz', nil]) # => (WHERE foo IN ('bar', 'baz') OR foo IS NULL)