var result = context.Blogs.Select(b => new { b.Id, b.Name }).ToList();
WHERE
LINQ Where
var filtered = context.Blogs.Where(b => b.IsActive).ToList();
ORDER BY
LINQ OrderBy/ThenBy
var ordered = context.Blogs.OrderBy(b => b.Name).ThenBy(b => b.Id).ToList();
GROUP BY
LINQ GroupBy
var grouped = context.Blogs.GroupBy(b => b.Category).Select(g => new { Category = g.Key, Count = g.Count() }).ToList();
HAVING
LINQ Where after GroupBy
var filteredGroups = context.Blogs.GroupBy(b => b.Category).Where(g => g.Count() > 1).Select(g => new { Category = g.Key, Count = g.Count() }).ToList();
JOIN
LINQ Join/GroupJoin
var joined = context.Blogs.Join(context.Posts, b => b.BlogId, p => p.BlogId, (b, p) => new { Blog = b, Post = p }).ToList();
LEFT JOIN
LINQ GroupJoin DefaultIfEmpty
var leftJoined = context.Blogs.GroupJoin(context.Posts, b => b.BlogId, p => p.BlogId, (b, posts) => new { Blog = b, Posts = posts.DefaultIfEmpty() }).SelectMany(x => x.Posts, (b, p) => new { Blog = b.Blog, Post = p }).ToList();
INSERT
DbSet.Add/AddRange
context.Blogs.Add(new Blog { Name = "New Blog" }); context.SaveChanges();
UPDATE
修改实体后SaveChanges
var blog = context.Blogs.Find(1); blog.Name = "Updated Blog"; context.SaveChanges();
DELETE
DbSet.Remove/RemoveRange
var blog = context.Blogs.Find(1); context.Blogs.Remove(blog); context.SaveChanges();
AGGREGATE FUNCTIONS (如 COUNT, MAX, MIN, SUM, AVG)
LINQ Aggregate Functions
var count = context.Blogs.Count(); var maxId = context.Blogs.Max(b => b.Id);
