![]() ![]() 1st point is also not our use case as its later pattern-matched in another function clausule. The important part of this check is that we all those cases: 2 maps. Thanks for reporting and the failing test and thanks for the investigation. In this we are checking if there are 2 different structs (which is not our use case). ![]() The solution is to return a tuple or a map with both post and extra_field keys. elixir - Getting a virtual field in Ecto calculated during a SQL Join Query - Stack Overflow Getting a virtual field in Ecto calculated during a SQL Join Query Ask Question Asked 6 years ago Modified 5 years, 11 months ago Viewed 4k times 2 This may be more of SQL question rather than an Elixir/Etco Question. It works like this: Users can submit Posts. select is more generic, so we check when executing. 1 Using Ecto v2.2.6, Phoenix 1.3 I have a Blog app with a Newsfeed. ![]() You can truly build some amazing things with these. The reason we can do the compile checking for subquery is that subqueries only allow a limited set of expressions. If youre interested in this, I definitely suggest reading into fragments, dynamic queries, and subqueries. There is documentation around this at, but I still had to muck about for a while.Defp subquery_select ( % does not have the key :extra_field |> join(:inner,, rc in subquery(most_recent_published_comment()),ĭef get_users_with_most_recent_published_comment() do in subquery (s) is already a valid ecto expression for join (see. (see syntaxes on Support where in (subquery) ectosql218 ). Its 'where x in (subquery)' rather than 'where x in (query)'. Is it also possible to create a table in the database for this model during runtime, i.e. subquery is a term in postgres and mysql documentation in this context. so the results look something like [Ĭomments: [%) According to this issue Dynamic Models in Phoenix Framework it is possible to dynamically create a model in Elixir using Module.create. However, the problem here is that it doesn't preload each user's most recent published comment - it only preloads the single most recent published comment and puts it on the associated user. Preload with Ecto with subquery and using a join from the main query. ![]() Ecto Query - Preload one associated object for a number of records. The closest I've been able to muster is # assume that my User model has a `has_many(:comments)` relationship definedĭefp preload_most_recent_comment(_user_ids) doĭef get_users_with_most_recent_comment() do Elixir & ecto: Subqueries or side loading and normalized json output in view. Say, for example, I have a data model with many users where each has many comments - the result I'm trying to achieve is a list of all users where each has only their most recent published comment preloaded. However, the subquery above can be written as a JOIN, which is supported by Ecto. I'm trying to write an Ecto query where I am querying for many records and for each record wish to preload only the most recent record from a related table however, things aren't quite working out as I'd like. From a quick perusal of the Ecto docs it looks like it is not currently possible: If you attempt to write it as where: p.id in subquery(foo), Ecto won’t accept such query. ![]()
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