Действительно ли это - хорошая идея изучить LINQ сначала, затем SQL?

SQL is a standard, learn the standard.

More precisely :

• learn database theory

• learn CODD algebra

• then pick up a "common database", do some tutorials on it, ...

I personnaly really like PostgreSQL tutorial

Learn SQL first, then LINQ.

That way you'll understand how LINQ-to-SQL is working behind the scenes, but you'll also know enough to be able to cope when LINQ can't do what you need.

Well, the 2 things are very different. LINQ (in the pure sense) isn't actually related to databases at all - it can be used quite happily just with in memory objects, or against web services, etc.

If you are mainly interested in writing better .NET code, then learn LINQ - but learn it properly - perhaps pick up C# in Depth, for example - which covers it very well in the last few chapters.

If you want to know about databases, then sure: learn SQL (such as TSQL) - but understand the differences. Databases are good if you need to write enterprise software, but not necessarily if you just want to do simple tasks.

edit re edit to the question

If you are just getting simple data in and out of the database, then you probably don't need to know much about SQL. Just use LINQ-to-SQL (or whatever tool), and let the ORM tooling worry about it.

Я утверждаю, что вы не можете эффективно использовать LINQ, если у вас нет знаний по SQL. Если вы не понимаете, как минимум, следующее, вы не можете эффективно запрашивать базу данных любым способом:

select
insert
delete
update
joins
group by
boolean algebra
relational theory
set theory

Изучение SQL даст вам необходимые концепции, даже если вы будете использовать LINQ позже.

Sql. Однако вы можете поиграть с linq pad некоторое время - это бесплатная программа, и вы поймете, что LINQ - хороший гибрид между SQL и C #