[wip] Create repository query guide with examples

data/guides.yml

@@ -54,6 +54,8 @@ categories:
       - path: overview
       - path: database-configuration
       - path: repositories
+      - path: query-examples
+        title: Query Examples
       - path: entities
       - path: data-types
       - path: postgresql

source/guides/models/query-examples.md

@@ -0,0 +1,73 @@
+---
+title: Guides - Query Examples
+---
+
+## Order
+
+For add `order` to your relation just call `#order` method with block:
+
+```ruby
+repo = UserRepository.new
+
+repo.users.order { created_at.desc }
+repo.users.order { created_at.asc }
+
+# you can set any field for order
+repo.users.order { name.asc }
+repo.users.order { last_name.asc }
+
+# you can use other relation for ordering
+repo.users.order(repo.books[:title].qualified.asc)
+```
+
+## SQL Functions
+
+You can use any SQL functions like `LIKE`, `ILIKE`, etc. For this call this functions in `where` block:
+
+```ruby
+repo = UserRepository.new
+
+repo.users.where { name.ilike('%anton%') }
+repo.users.where { name.like('%anton%') }
+
+# you can call IN functions too
+repo.users.where { id.in(1) }
+repo.users.where { id.in(1..100) }
+repo.users.where { id > 1 || id < 100 }
+
+# you can call NOT functions too
+repo.users.where { id.not(1) }
+repo.users.where { id.not(1..100) }
+```
+
+```ruby
+name = repo.user[:name].qualified
+repo.where { length(name) > 10) }
+```
+
+```ruby
+repo.users.where { id.in(1..100) }.limit(100)
+```
+
+```ruby
+repo.users.where(id: 1) == repo.users.by_pk(1)
+```
+
+## Joins
+https://stackoverflow.com/questions/43080678/join-query-in-hanami-model/43156257#43156257
+
+```ruby
+
+repo.users.join(:posts)
+repo.users.join(:posts, id: :user_id)
+repo.users.join(repo.posts)
+```
+
+also you can use `#inner_join` method
+
+## Group by
+
+Examples with groyp you can find here:
+https://github.com/rom-rb/rom-sql/blob/master/spec/unit/relation/group_spec.rb
+
+Also you can't use `#select` in hanami model. YOu need to use `#project` instead