将SQL语句转换为Linq-2-Sql

Question

如何将下面的SQL语句翻译成L2S？

SELECT DefaultCode, MAX(EffectiveDt) AS EffectiveDt
FROM tblDF_DefaultSetting
GROUP BY DefaultCode

Answer 1

您希望在DefaultCode上使用GroupBy运算符，并使用Select运算符创建一个新的匿名类型，其中包含您感兴趣的两个值。

dataContext.tblDF_DefaultSetting
    .GroupBy(x => x.DefaultCode)
    .Select(x => new { DefaultCode = x.Key, EffectiveDt = x.Max(x => x.EffectiveDt) });