linq - 代码优先中实体框架中的等效 sql 代码插入/sql

Question

等效于代码优先中实体框架中的以下代码

INSERT INTO TableA (a,b)
SELECT a,b
FROM TableB
WHERE a=10

Answer 1

我相信您正在尝试根据条件从中选择几列TableB，然后将所有这些对象添加到TableA，可以执行以下操作：

//Create list of TableA objects after selecting and projecting from TableB
var list = db.TableB.Where(t => t.a == 10)
                    .Select(r => new TableA() { A = r.a, B = r.b })
                    .ToList();
//Add those items to TableA through DataContext
foreach (var item in list)
    db.TableA.AddObject(item);
//Call Save
db.SaveChanges();