How to select data from two tables in Ecto

问题

I trying to write Ecto query which will be select data from two tables at the same time. Like Select t1.*,t2.* from table1 t1,table2 t2 where t1.id=1 and t2.id=2 I can't find solution, found only way to write raw SQL and it's looks like not good.

Like variant -using preload, but it's spawn additional query.

comments_query = from c in Comment, order_by: c.published_at
Repo.all from p in Post, preload: [comments: ^comments_query]

Thanks for any ideas

回答1:

Try this from Ecto.Query

https://hexdocs.pm/ecto/Ecto.Query.html#join/5

from t1 in Table1,
   join: t2 in Table2, on: t1.t2_id == t2.id,
   select: {t1.title, t2.text}

来源：https://stackoverflow.com/questions/36240347/how-to-select-data-from-two-tables-in-ecto