SELECT StudentHistoryId, StudentId, Grade, CreatedAt, ModifiedAt, ModifiedBy, Active
FROM TABLENAME TN
INNER JOIN ( SELECT StudentId, MAX(ModifiedAt) AS ModifiedAt FROM TABLENAME GROUP BY StudentId) M
ON TN.开发者_开发问答StudentId = M.StudentId AND TN.ModifiedAt = M.ModifiedAt
Here's a direct translaton:
var subquery = from tn in dc.TABLENAME
group tn by tn.StudentId into g
select new { StudentId = g.Key, ModifiedAt = g.Max(x => x.ModifiedAt) };
var query = from tn in dc.TABLENAME
join m in subquery
on new { tn.StudentId, tn.ModifiedAt }
equals new { m.StudentId, m.ModifiedAt }
select new
{
tn.StudentHistoryId,
tn.StudentId,
tn.Grade,
tn.CreatedAt,
tn.ModifiedAt,
tn.ModifiedBy,
tn.Active
};
精彩评论