實體框架加入3個表我想加入三張桌子，但我無法理解這個方法......我完成了加入2個表 var entryPoint = dbContext.tbl_EntryPoint .Join(dbContext.tbl_Entry,
c => c.EID,
cm => cm.EID,
(c, cm) => new
{
UID = cm.OwnerUID,
TID = cm.TID,
EID = c.EID,
}).
Where(a => a.UID == user.UID).Take(10);我想在TID PK中包含tbl_Title表并獲取Title字段。非常感謝
3 回答
慕神8447489
TA貢獻1780條經驗 獲得超1個贊
我認為使用基于語法的查詢會更容易：
var entryPoint = (from ep in dbContext.tbl_EntryPoint
join e in dbContext.tbl_Entry on ep.EID equals e.EID
join t in dbContext.tbl_Title on e.TID equals t.TID where e.OwnerID == user.UID select new {
UID = e.OwnerID,
TID = e.TID,
Title = t.Title,
EID = e.EID }).Take(10);你應該添加orderby子句，以確保Top(10)返回正確的前十項。
紅顏莎娜
TA貢獻1842條經驗 獲得超13個贊
這是未經測試的，但我相信語法應該適用于lambda查詢。當您使用此語法連接更多表時，您必須深入查看新對象以獲得要操作的值。
var fullEntries = dbContext.tbl_EntryPoint .Join(
dbContext.tbl_Entry,
entryPoint => entryPoint.EID,
entry => entry.EID,
(entryPoint, entry) => new { entryPoint, entry }
)
.Join(
dbContext.tbl_Title,
combinedEntry => combinedEntry.entry.TID,
title => title.TID,
(combinedEntry, title) => new
{
UID = combinedEntry.entry.OwnerUID,
TID = combinedEntry.entry.TID,
EID = combinedEntry.entryPoint.EID,
Title = title.Title
}
)
.Where(fullEntry => fullEntry.UID == user.UID)
.Take(10);
絕地無雙
TA貢獻1946條經驗 獲得超4個贊
var entryPoint = (from ep in dbContext.tbl_EntryPoint
join e in dbContext.tbl_Entry on ep.EID equals e.EID
join t in dbContext.tbl_Title on e.TID equals t.TID where e.OwnerID == user.UID select new {
UID = e.OwnerID,
TID = e.TID,
Title = t.Title,
EID = e.EID }).Take(10);- 3 回答
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