Linq，SQL和ISNULL

Question

我試圖找出Linq。我只有很小的成功，大部分文章都是針對C＃而不是幫助的。

我試圖做以下工作;

Dim query = From r In db.eq_list 
       Join s In db.interview_main On r.CLIENTCODE Equals s.CLIENTCODE And r.CONTROL Equals s.CONTROL 
       Select New With {r.UserName, r.CONTROL, r.CLIENTCODE, r.CLIENTLOCATION, r.IDATETIME, r.FIRSTNAME, 
        r.LASTNAME, If(String.IsNullOrEmpty(s.Code), 0, s.Code)} 


    dgvOnHold.DataSource = query.ToList 

問題是IF部分。這部分可以在數據庫中爲NULL，但我希望它返回爲0如果爲NULL。我把它放到一個只讀的Datagridview中。原始的SQL如下;

SELECT r.ID,r.UserName,r.CONTROL,r.CLIENTCODE,r.CLIENTLOCATION,r.IDATETIME,r.FIRSTNAME,r.LASTNAME,ISNULL(s.CODE,0) AS CODE 
FROM system.eq_list AS r 
LEFT JOIN interview.main AS s ON r.CLIENTCODE = s.CLIENTCODE AND r.CONTROL = s.CONTROL; 

Answer 1

目前無法檢查，但怎麼樣？

Dim query = From r In db.eq_list 
      Join s In db.interview_main On r.CLIENTCODE Equals s.CLIENTCODE And r.CONTROL Equals s.CONTROL 
      Select New With {r.UserName, r.CONTROL, r.CLIENTCODE, r.CLIENTLOCATION, r.IDATETIME, r.FIRSTNAME, 
       r.LASTNAME, If(s.Code is Nothing, 0, s.Code)} 


dgvOnHold.DataSource = query.ToList