Programming Ecto

Query Basics

Let’s start with the basics. We’ll take a quick look at Ecto’s query syntax, then start writing some simple queries, including some that integrate user input.

The Query module uses Elixir macros to create a DSL (domain-specific language) that sits right in your Elixir code. The DSL syntax feels a lot like Elixir, but it’s a little more fluid and makes writing queries feel more natural.

For example, here’s a SQL query based on the data model in our sample app. You can run this in a Postgres console to see what it does:

priv/examples/query_01.exs

SELECT t.id, t.title, a.title
  FROM tracks t
  JOIN albums a ON t.album_id = a.id
  WHERE t.duration > 900;

And here’s that same query written in Ecto:

query = from ...