Linq查询以获取最新的eact缺陷ID

Question

在al_jira_defect_out表中，我有Batch_Insert_Timestamp，AL_Defect_ID列以及该表中的其他columns.And，将有不同Batch_Insert_Timestamp的重复AL_Defect_IDs。

按照下面的linq代码，我得到了所有的记录，它们是Jira_Status == 0

var defects = (from d in db.al_jira_defect_out
    join p in db.al_jira_ref_defect_project on d.Defect_Product_ID.ToString() equals p.al_product_id
    join t in db.al_jira_ref_defect_type on d.Defect_Type_ID equals t.type
    where d.Jira_Status == 0
    select new Issue
    {
        fields = new CreateIssue
        {
            project = new Project
            {
                key = g.jira_project_key
            },
            issuetype = new Issuetype()
            {
                name = t.jira_equivalent
            },
            description = d.Defect_ShortDesc,
            summary = d.Defect_DetailDesc,
            versions = new List<Versions>
            {
                new Versions {name = d.Defect_Release_DetectedIn}
            },
            priority = new Priority
            {
                name = d.Defect_Severity_Name
            },
            customfield_10182 = d.AL_Defect_ID.ToString(),
        }
    }).Select().ToList();

我正在获得与AL_Defect_IDs副本的记录。但是我需要每个包含所有必需列的最新recordsMax(d.Batch_Insert_Timestamp)，请帮助我获得linq查询。

Answer 1

如果您在AL_Defect_ID上分组，您可以按Batch_Insert_Timestamp订购，并接受最后一个(最新)一个：

var defects = (from d in db.al_jira_defect_out
               join p in db.al_jira_ref_defect_project on d.Defect_Product_ID.ToString() equals p.al_product_id
               join t in db.al_jira_ref_defect_type on d.Defect_Type_ID equals t.type
               where d.Jira_Status == 0
               group new { d, p, t } on d.AL_Defect_ID into dptg
               let dpt = (from dpt in dptg order by dpt.d.Batch_Insert_Timestamp select dpt).Last()
               select new // ... whatever using dpt

示例代码在p中不使用select，因此可以将其排除在group之外。