3 ms·

It is! One suggestion to make it even more convincing: I'd love to see the SQL statement it compiles to.

• leeuw01 3y ago
  This +1. I've been burned before when using ORMs which translate simple-looking queries to terribly inneficient SQL statements underwater.
  • danielvaughn 3y ago
    Yeah I’m a web dev, and recently I found out the most popular JS ORM doesn’t produce joins. It’ll just execute multiple queries in sequence. I don’t know how common that is in the ORM landscape but for me that’s a deal breaker.
    • smaddox 3y ago
      Common enough to have a name: the N+1 query problem.
      • Izkata 3y ago
        1+N is clearer I think, and what I remember seeing in the past - it matches what's actually happening with this problem. First time I saw N+1 sometime around a year ago, I had no idea it referred to the same thing and thought it was something different. N+1 looks like an issue with aggregation after a parallel run, something I've encountered with celery tasks before.
    • setr 3y ago
      That’s just a direct result of lazy loading — if you don’t grab the related objects in the initial query, then there’s no joins to be had. Most ORMs do lazy loading by default, but also have a way of doing eager loading — either requiring the nested object to always be loaded as well, or dropping down to some pseudo-sql. In c#/EFCore, I always prefer to avoid lazy loading and just write LINQ, and just use the ORM to map the resultset back to objects
• Timon3 3y ago
  For reference, this is the output: WITH table_1 AS ( SELECT customer_id, total, total - 0.8 AS _expr_0 FROM invoices WHERE invoice_date >= DATE '1970-01-16' ), table_0 AS ( SELECT COALESCE(SUM(_expr_0), 0) AS sum_income, customer_id FROM table_1 WHERE _expr_0 > 1 GROUP BY customer_id ORDER BY sum_income DESC LIMIT 10 ) SELECT c.customer_id, CONCAT(c.last_name, ', ', c.first_name) AS name, table_0.sum_income, version() AS db_version FROM table_0 JOIN customers AS c ON table_0.customer_id = c.customer_id ORDER BY table_0.sum_income DESC