我需要一些幫助來編寫此linq查詢

Question

我有這個SQL查詢

select case when AllowanceId is null then 2  else AllowanceId end as AllowanceId
     , d.descen as domdescen
     , t.descen as typdescen
     , case when qty is null then 0 else qty end as qty
     , u.descen as unidescen
from (select t.allowancetypeid, d.allowancedomainid 
      from allowancedomain as d, allowancetype as t
      where t.allowancetypeid in (1,2) and d.active = 1 and t.active = 1) as a left join 
    allowanceqty as q on a.allowancetypeid = q.allowancetypeid and
                         a.allowancedomainid = q.allowancedomainid and 
                         q.allowanceid = 2 inner  join 
    allowancedomain as d on a.allowancedomainid = d.allowancedomainid
    inner  join 
    allowancetype as t on a.allowancetypeid = t.allowancetypeid
    inner join
    unit as u on case when q.unitid is null then 1 else q.unitid end = u.unitid

該查詢中有一個變量，它在select子句（第一行）中為2，在from子句中（中間）為“ = 2”

我寫了我想要的東西，下面看我的答案

Answer 1

經過長時間的嘗試/重試/嘗試/重試，這就是我想要的...。

from a in (from d in AllowanceDomains _
        from t in AllowanceTypes _
        where (new integer(){1,2}).contains(t.AllowanceTypeID) and t.active = true and d.active=true _
        select  t.allowancetypeid,tdescen =t.descen, d.allowancedomainid,ddescen=d.descen)  _
group join qqq in AllowanceQties on new with {.k1 = a.allowancetypeid, .k2 = a.allowancedomainid, .k3 = 2} equals _
                            new with {.k1 = qqq.allowancetypeid, .k2 = qqq.allowancedomainid, .k3 = qqq.allowanceid} into qq = group _
from q in qq.DefaultIfEmpty _
join u in units on if(object.equals(q.unitid,nothing),1,q.unitid) equals u.unitid _
select  AllowanceID =if(object.equals(q.AllowanceID,nothing),2,q.AllowanceID) ,a.tdescen,a.ddescen,qty = if(object.equals(q.qty,nothing),0,q.qty),u.descen

Answer 2

Linqer是您的朋友。 http://www.sqltolinq.com 。 它允許您將幾乎所有的sql轉換為linq，並可以與數據庫和dbml一起使用。 到目前為止，這從未使我失敗。 它不是免費產品，但物有所值。 [我與Linqer沒有任何關聯]