下面左连接翻译成linq
select a.*,b.Level1 from HR_POSITION_CODE a
left join POSITONSEQ_LEVEL_COEF_V2 b on a.position_code_id=b.code

[解决办法]

C# code

//easy...var query= from a in HR_POSITION_CODE           join b in POSITONSEQ_LEVEL_COEF_V2           on a.position_code_id equals b.code into g           from b in g.DefaultIfEmpty()           select new             {            a,                Level1=b==null?"":b.Level1               };
[解决办法]
http://msdn.microsoft.com/en-us/vcsharp/ee908647#leftouterjoin
[解决办法]
探讨

select a.*,b.Level1 from HR_POSITION_CODE a  
left join POSITONSEQ_LEVEL_COEF_V2 b on a.position_code_id=b.code