Correct code snippets

_posts/2018-07-25-ecto-query-composition.md

@@ -32,7 +32,7 @@ defmodule Posts do
  import Ecto.Query
 
  defp base_query do
- (from p in Post)
+ from p in Post
  end
 end
 ```
@@ -75,19 +75,21 @@ defp build_query(query, criteria) do
  Enum.reduce(criteria, query, &compose_query/2)
 end
 
-defp compose_query(query, {"title", title}) do
- where(query, [p], fragment("? ILIKE '%?%'", p.title, title))
+defp compose_query({"title", title}, query) do
+ where(query, [p], ilike(p.title, ^"%#{title}%"))
 end
 
-defp compose_query(query, {"tags", tags}) do
- join(query, :left, [p], t in assoc(p, :tags), on: t.name in ^tags)
+defp compose_query({"tags", tags}, query) do
+ query
+ |> join(:left, [p], t in assoc(p, :tags))
+ |> where([_p, t], t.name in ^tags)
 end
 
-defp compose_query(query, {key, value}) when key in ~w(draft id) do
- where(query, [p], {String.to_atom(key), value})
+defp compose_query({key, value}, query) when key in ~w(draft id) do
+ where(query, [p], ^{String.to_atom(key), value})
 end
 
-defp compose_query(query, _unsupported_param) do
+defp compose_query(_unsupported_param, query) do
  query
 end
 ```
@@ -128,26 +130,29 @@ defmodule Posts do
  end
 
  defp base_query do
- (from p in Post)
+ from p in Post
  end
 
- defp build_query(criteria) do
+ defp build_query(query, criteria) do
  Enum.reduce(criteria, query, &compose_query/2)
  end
 
- defp compose_query(query, {"title", title}) do
- where(query, [p], fragment("? LIKE '%?%'", p.title, title))
+ defp compose_query({"title", title}, query) do
+ where(query, [p], ilike(p.title, ^"%#{title}%"))
  end
 
- defp compose_query(query, {"tags", tags}) do
- join(query, :left, [p], t in assoc(p, :tags), on: t.name in ^tags)
+ defp compose_query({"tags", tags}, query) do
+ query
+ |> join(:left, [p], t in assoc(p, :tags))
+ |> where([_p, t], t.name in ^tags)
  end
 
- defp compose_query(query, {key, value}) when key in ~w(draft id) do
- where(query, [p], {String.to_atom(key), value})
+ defp compose_query({key, value}, query) when key in ~w(draft id) do
+ field = String.to_atom(key)
+ where(query, [p], ^{field, value})
  end
 
- defp compose_query(query, _unsupported_param) do
+ defp compose_query(_unsupported_param, query) do
  query
  end