对linq的SQL查询(with/as，update)

var query = from p in dbContext.Persons
            where p.Age > 18
            select p;

// 使用WITH定义临时查询结果
var queryWith = with adults as (
                    select p from dbContext.Persons p where p.Age > 18
                )
                select p from adults;

// 使用WITH定义多个临时查询结果
var queryMultipleWith = with adults as (
                            select p from dbContext.Persons p where p.Age > 18
                        ),
                        maleAdults as (
                            select p from adults where p.Gender == "Male"
                        )
                        select p from maleAdults;

var query = from p in dbContext.Persons
            where p.Age > 18
            select new {
                FullName = p.FirstName + " " + p.LastName,
                p.Age
            };

// 使用AS给查询结果列设置别名
var queryWithAs = from p in dbContext.Persons
                  where p.Age > 18
                  select new {
                      FullName = p.FirstName + " " + p.LastName,
                      Age = p.Age
                  };

dbContext.Persons
    .Where(p => p.Age > 18)
    .Update(p => new Person { Age = p.Age + 1 });