C# 使用联接对Linq进行Sql查询
实际上,我正在尝试将我的C# 使用联接对Linq进行Sql查询,c#,asp.net,.net,linq,linq-to-entities,C#,Asp.net,.net,Linq,Linq To Entities,实际上,我正在尝试将我的SQL查询转换为Linq。 我的查询包含3个表: 我的问题是: select ST.TEMPLATE_ID,ST.TEMPLATE_NAME,ST.CREATED_DATE ,count(distinct SQ.QUESTION_ID) as NOQ ,( select count(*) from SURVEY_EMAIL_BLAST SEB where SEB.TEMPLATE_ID=ST.TEMPLATE_ID and SEB.STATUS='Delivered'
SQL
查询转换为Linq
。
我的查询包含3个表:
我的问题是:
select ST.TEMPLATE_ID,ST.TEMPLATE_NAME,ST.CREATED_DATE
,count(distinct SQ.QUESTION_ID) as NOQ
,(
select count(*) from SURVEY_EMAIL_BLAST SEB
where SEB.TEMPLATE_ID=ST.TEMPLATE_ID
and SEB.STATUS='Delivered'
) as [Sent]
,(
select count(*) from SURVEY_EMAIL_BLAST SEB
where SEB.TEMPLATE_ID=ST.TEMPLATE_ID
and (SEB.EMAIL_RESULT_TEXT='Viewed' or seb.EMAIL_RESULT_TEXT='Completed')
) as [View]
,(
select count(*) from SURVEY_EMAIL_BLAST SEB
where SEB.TEMPLATE_ID=ST.TEMPLATE_ID
and SEB.EMAIL_RESULT_TEXT='Completed'
) as [Reply]
from SURVEY_TEMPLATE ST left outer join SURVEY_QUESTION SQ
on ST.TEMPLATE_ID=SQ.TEMPLATE_ID
group by ST.TEMPLATE_ID,ST.TEMPLATE_NAME,ST.CREATED_DATE
order by ST.TEMPLATE_ID
我的结果是:
我的linq查询是这样的:
var data111 = (from st in VDC.SURVEY_TEMPLATE
join sq in VDC.SURVEY_QUESTION on new { TEMPLATE_ID = st.TEMPLATE_ID } equals new { TEMPLATE_ID = (Int64)sq.TEMPLATE_ID } into fg
from z in fg.DefaultIfEmpty()
group st by new
{
st.TEMPLATE_ID,
st.TEMPLATE_NAME,
st.CREATED_DATE,
} into g
orderby
g.Key.TEMPLATE_ID
select new
{
TEMPLATE_ID = (Int64?)g.Key.TEMPLATE_ID,
g.Key.TEMPLATE_NAME,
CREATED_DATE = (DateTime?)g.Key.CREATED_DATE,
Sent = (Int64?)
(from seb in VDC.SURVEY_EMAIL_BLAST
where
seb.SURVEY_TEMPLATE.TEMPLATE_ID == g.Key.TEMPLATE_ID &&
seb.STATUS == "Delivered"
select new
{
seb
}).Count(),
View = (Int64?)
(from seb in VDC.SURVEY_EMAIL_BLAST
where
seb.SURVEY_TEMPLATE.TEMPLATE_ID == g.Key.TEMPLATE_ID && (
seb.EMAIL_RESULT_TEXT == "Viewed" ||
seb.EMAIL_RESULT_TEXT == "Completed")
select new
{
seb
}).Count(),
Reply = (Int64?)
(from seb in VDC.SURVEY_EMAIL_BLAST
where
seb.SURVEY_TEMPLATE.TEMPLATE_ID == g.Key.TEMPLATE_ID &&
seb.EMAIL_RESULT_TEXT == "Completed"
select new
{
seb
}).Count()
}).ToList();
现在我的结果是:
我无法显示NOQ
列。
有人能帮我吗
首先,通过来源将
z
添加到组中:
group new { st , z } by new
{
st.TEMPLATE_ID,
st.TEMPLATE_NAME,
st.CREATED_DATE,
} into g
然后使用它在选择中获取NOQ
:
NOQ = g.Select(x => x.z.QUESTION_ID).Distinct().Count()
或者将st
替换为z
,因为您以后不会在任何地方使用st
:
group z by new
{
st.TEMPLATE_ID,
st.TEMPLATE_NAME,
st.CREATED_DATE,
} into g
但它也需要更改选择
:
NOQ = g.Select(x => x.QUESTION_ID).Distinct().Count()
老实说,你的问题看起来很糟糕。你确定不能做得更好吗?当我用new编写组new{st,sq}by new:sq不是intellisense的,错误是无法将lambda表达式转换为类型“不等式比较器”@RealSteel OK,我错过了DefaultIfEmpty
部分。尝试使用z
而不是sq
。即使我也这样认为:)我需要更改我的查询:)