linq查詢從多個表中獲取計數

Question

我有多個表，從中我想從查詢中的特定ID表中獲取計數，如下所示：

         var jobsPostList = (from jobposting in reslandEntities.JOB_POSTING
                            join skill in reslandEntities.SKILL on jobposting.SKILL_ID equals skill.ID
                            from  req in reslandEntities.REQUIREMENT_POSTING 
                            where jobposting.POSTED_BY_ID == RES_ID && jobposting.POSTED_BY == "CLIENT"
                            && jobposting.IS_DELETED == "N"
                            && jobposting.STAT!="DRAFT"
                            && req.JOB_ID==jobposting.ID
                            select new PostJobModel
                            {
                                ID = jobposting.ID,
                                JOB_ID = jobposting.JOB_ID,
                                POST_TITLE = jobposting.TITLE,
                                POST_DT = jobposting.POST_DT,
                                POST_END_DT = jobposting.POST_END_DT,
                                TECH_SKILLS = skill.TECH_SKILLS,
                                POSITIONS_CNTS = jobposting.POSITIONS_CNT,
                                DURATION = jobposting.DURATION,
                                LOCATION = jobposting.LOCATION,
                                STAT = jobposting.STAT,
                                DT_CR = jobposting.DT_CR,
                                SUB_COMP_COUNT = reslandEntities.REQUIREMENT_POSTING.Where(m => m.JOB_ID == jobposting.ID).Select(m => m.COMP_ID).Count(),
                                COMP_COUNT = companyCount,
                                CAND_COUNT = reslandEntities.SUBSCRIBER_RESOURCE_SUBMISSION.Where(m=>m.CLIENT_JOB_POSTINGID==req.ID).Select(m=>m.RES_ID).Count()
                            }).Distinct().ToList();

我想從“REQUIREMENT POSTING”表和另一個表“SUBSCRIBER_RESOURCE_SUBMISSION”表中獲取COUNT，我已嘗試過如上所述但沒有得到正確的結果，獲得多行而不是一行。 請幫助我。

Answer 1

我認為這對你有用......

 var jobsPostList = (from jobposting in reslandEntities.JOB_POSTING
                            join skill in reslandEntities.SKILL on jobposting.SKILL_ID equals skill.ID                                
                            join grpComp in
                                (
                                  from jobsent in reslandEntities.REQUIREMENT_POSTING
                                  group jobsent by jobsent.JOB_ID into grp
                                  select new { grp.Key, count = grp.Select(m => m.COMP_ID).Count() }
                                ) on jobposting.ID equals grpComp.Key
                            let result = (
                            from sub in reslandEntities.SUBSCRIBER_RESOURCE_SUBMISSION
                            join req in reslandEntities.REQUIREMENT_POSTING on sub.CLIENT_JOB_POSTINGID equals req.ID
                            where req.JOB_ID == jobposting.ID
                            select sub.RES_ID
                            )
                            where jobposting.POSTED_BY_ID == RES_ID && jobposting.POSTED_BY == "CLIENT"
                            && jobposting.IS_DELETED == "N"
                            && jobposting.STAT!="DRAFT"

                            select new PostJobModel
                            {
                                ID = jobposting.ID,
                                JOB_ID = jobposting.JOB_ID,
                                POST_TITLE = jobposting.TITLE,
                                POST_DT = jobposting.POST_DT,
                                POST_END_DT = jobposting.POST_END_DT,
                                TECH_SKILLS = skill.TECH_SKILLS,
                                POSITIONS_CNTS = jobposting.POSITIONS_CNT,
                                DURATION = jobposting.DURATION,
                                LOCATION = jobposting.LOCATION,
                                STAT = jobposting.STAT,
                                DT_CR = jobposting.DT_CR,
                                SUB_COMP_COUNT = grpComp.count,
                                COMP_COUNT = companyCount,
                                CAND_COUNT = result.Count()
                            }).ToList();