EF Core 3.1 / MySQL - 在 Distinct() 之后忽略 OrderByDescending

Question

I run this query

       var query = await _db.Production
                .OrderByDescending(q => q.Id)
                .Where(q => q.Industry > 0)
                .Select(m => m.FromCompany).Distinct().Take(10).ToListAsync()

And get the following

 Executed DbCommand (64ms) [Parameters=[@__p_0='?' (DbType = Int32)], CommandType='Text', CommandTimeout='30'] SELECT DISTINCT `j`.`from_company` FROM `production` AS `j` WHERE (`j`.`Industry` > 0) LIMIT @__p_0

However, I expected to see

ORDER BY production . id DESC

Which I did at the begging

.OrderByDescending(q => q.Id)

How can I order after distinct?

---

Update.

If I put order after distinct, I will not be able to sort by ID: Error CS1061 'int' does not contain a definition for 'Id' and no accessible extension method 'Id' accepting a first argument of type 'int' could be found (are you missing a using directive or an assembly reference?)

Answer 1

I run this query

       var query = await _db.Production
                .OrderByDescending(q => q.Id)
                .Where(q => q.Industry > 0)
                .Select(m => m.FromCompany).Distinct().Take(10).ToListAsync()

And get the following

 Executed DbCommand (64ms) [Parameters=[@__p_0='?' (DbType = Int32)], CommandType='Text', CommandTimeout='30'] SELECT DISTINCT `j`.`from_company` FROM `production` AS `j` WHERE (`j`.`Industry` > 0) LIMIT @__p_0

However, I expected to see

ORDER BY production . id DESC

Which I did at the begging

.OrderByDescending(q => q.Id)

How can I order after distinct?

---

Update.

If I put order after distinct, I will not be able to sort by ID: Error CS1061 'int' does not contain a definition for 'Id' and no accessible extension method 'Id' accepting a first argument of type 'int' could be found (are you missing a using directive or an assembly reference?)

Answer 2

PS I've reported this "issue"

Now it is "fixed" and people will get warnings in .net 6

https://github.com/dotnet/efcore/pull/24160