public object GetListAdmin() { //return db_C56.Admins // .Where(a => a.Status != "D").ToList(); var query1 = db_C56.Admins.Join(db_C56.Area, a => a.AreaID, ar => ar.ID, (a, ar) => new { userName = a.UserName, pwd = a.Password, dName = a.DisplayName, areaId = a.AreaID, hasNode = a.HasNode, roleName = a.RoleName, status = a.Status, areaName = ar.Name }); var query = from a in db_C56.Admins join ar in db_C56.Area on a.AreaID equals ar.ID where a.Status != "D" select new { userName = a.UserName, pwd = a.Password, dName = a.DisplayName, areaId = a.AreaID, hasNode = a.HasNode, roleName = a.RoleName, status = a.Status, areaName = ar.Name }; return query.ToList().Select(C => new Admin { UserName = C.userName, Password = C.pwd, DisplayName = C.dName, AreaID = C.areaId, AreaPath = C.areaName, HasNode = C.hasNode, RoleName = C.roleName, Status = C.status, }); }
from v in Pdt_Versions join t in Tb_TypeDics on v.TypeName equals t.TypeName into ignored from i in ignored.DefaultIfEmpty() where v.Status != "D" select new { ID = v.ID, VersionName = v.VersionName, VersionCode = v.VersionCode, DownloadName = v.DownloadName, DownloadURL = v.DownloadURL, VType = v.VType, TypeName = v.TypeName, DisplyTypeName = i.DisplyTypeName, }
Linq 多层嵌套查询
var query1 = from p in dbContent.PostService where p.post_type == "product" && (from ot1 in dbContent.OrderItemmetaService where (from ot2 in dbContent.OrderItemsService where ot2.order_item_type == "line_item" && (from p1 in dbContent.PostService where p1.post_type == "shop_order" && p1.post_author == userid && p1.post_status == "wc-completed" select p1.ID).Contains(ot2.order_id) select ot2.order_item_id).Contains(ot1.meta_id) select ot1.meta_value).Contains(p.ID) select new { id = p.ID, name = p.post_title }; var query2 = dbContent.PostService.Where(p => p.post_type == "product" && (dbContent.OrderItemmetaService.Where(ot1 => (dbContent.OrderItemsService.Where(ot2 => ot2.order_item_type == "line_item" && (dbContent.PostService.Where(p1 => p1.post_type == "shop_order" && p1.post_author == userid && p1.post_status == "wc-completed").Select(p1 => p1.ID).Contains(ot2.order_item_id)) ).Select(ot2 => ot2.order_item_id).Contains(ot1.meta_id)) ).Select(ot1 => ot1.meta_value).Contains(p.ID)) ).Select(p => new { id = p.ID, name = p.post_title }).ToList();
Left Join 查询
from d in Doctors
join c in (
(from t in Commentaries where t.State != 'D' group t by new { t.DoctorID } into g
select new {
DoctorID = (Int64?)g.Key.DoctorID,
Total = (Int32?)g.Sum(p => p.Rating),
Evaluate = (System.Double?)g.Average(p => p.Rating)
})) on new { UserID = d.UserID } equals new { UserID = (Int64)c.DoctorID }into a_join
from p in a_join.DefaultIfEmpty()
select new {
d.ID,
UserID = (Int64?)d.UserID,
d.Name,
Evaluate = ((int?)p.Evaluate ?? (int?)0)
}
Lambda表达式
Doctors
.GroupJoin (
Commentaries
.Where (t => ((Int32)(t.State) != 68))
.GroupBy (
t =>
new
{
DoctorID = t.DoctorID
}
)
.Select (
g =>
new
{
DoctorID = (Int64?)(g.Key.DoctorID),
Total = (Int32?)(g.Sum (p => p.Rating)),
Evaluate = (Double?)(g.Average (p => p.Rating))
}
),
d =>
new
{
UserID = d.UserID
},
c =>
new
{
UserID = (Int64)(c.DoctorID)
},
(d, a_join) =>
new
{
d = d,
a_join = a_join
}
)
.SelectMany (
temp0 => temp0.a_join.DefaultIfEmpty (),
(temp0, p) =>
new
{
ID = temp0.d.ID,
UserID = (Int64?)(temp0.d.UserID),
Name = temp0.d.Name,
Evaluate = ((Int32?)(p.Evaluate) ?? (Int32?)0)
}
)
======================================================================
多个left join
from d in Doctors
join f in Functions on new { FunctionID = d.FunctionID } equals new { FunctionID = f.ID } into b_join
from f in b_join.DefaultIfEmpty()
join c in (
(from t in Commentaries where t.State != 'D' group t by new {t.DoctorID } into g
select new {
DoctorID = (Int64?)g.Key.DoctorID,
Total = (Int32?)g.Sum(p => p.Rating),
Evaluate = (System.Double?)g.Average(p => p.Rating)
})) on new { UserID = d.UserID } equals new { UserID = (Int64)c.DoctorID } into a_join
from c in a_join.DefaultIfEmpty()
select new {
d.ID,
UserID = (Int64?)d.UserID,
d.AvatarPic,
d.Name,
f.Title,
f.ContentDescribe,
Evaluate = ((int?)c.Evaluate ?? (int?)0)
}
Lambda表达式
.GroupJoin (
Functions,
d =>
new
{
FunctionID = d.FunctionID
},
f =>
new
{
FunctionID = f.ID
},
(d, b_join) =>
new
{
d = d,
b_join = b_join
}
)
.SelectMany (
temp0 => temp0.b_join.DefaultIfEmpty (),
(temp0, f) =>
new
{
temp0 = temp0,
f = f
}
)
.GroupJoin (
Commentaries
.Where (t => ((Int32)(t.State) != 68))
.GroupBy (
t =>
new
{
DoctorID = t.DoctorID
}
)
.Select (
g =>
new
{
DoctorID = (Int64?)(g.Key.DoctorID),
Total = (Int32?)(g.Sum (p => p.Rating)),
Evaluate = (Double?)(g.Average (p => p.Rating))
}
),
temp1 =>
new
{
UserID = temp1.temp0.d.UserID
},
c =>
new
{
UserID = (Int64)(c.DoctorID)
},
(temp1, a_join) =>
new
{
temp1 = temp1,
a_join = a_join
}
)
.SelectMany (
temp2 => temp2.a_join.DefaultIfEmpty (),
(temp2, c) =>
new
{
ID = temp2.temp1.temp0.d.ID,
UserID = (Int64?)(temp2.temp1.temp0.d.UserID),
AvatarPic = temp2.temp1.temp0.d.AvatarPic,
Name = temp2.temp1.temp0.d.Name,
Title = temp2.temp1.f.Title,
ContentDescribe = temp2.temp1.f.ContentDescribe,
Evaluate = ((Int32?)(c.Evaluate) ?? (Int32?)0)
}
)