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linq to EF groupjoin

//using System.Data.Objects.SqlClient; private void btnLike_Click(object sender, EventArgs e) { NorthwindEntities en = new NorthwindEntities(); var v = en.Employees.Where(x => SqlFunctions.PatIndex("%a%e%", x.FirstName) > 0); ...

var query = from a in GME_TB_ProductInfo join b in ( from c in GME_TB_ProductInfoDtl group c by c.ProductCode into g select new { ProductCode = g.Key, ProductInfoDtl = g.OrderBy(x => x.BeginDate).FirstOrDefault() } ) on a.Produ...

按需求,直接选一个吧 GROUP: Employees .GroupBy (e => e.JobTitle) .Select ( g => new { JobTitle = g.Key, TotalVacations = g.Sum (e => (Int32)(e.VacationHours)) } ) Distinct: Employees .Select (e => e.JobTitle) .Distinct ()

按需求,直接选一个吧 GROUP: Employees .GroupBy (e => e.JobTitle) .Select ( g => new { JobTitle = g.Key, TotalVacations = g.Sum (e => (Int32)(e.VacationHours)) } ) Distinct: Employees .Select (e => e.JobTitle) .Distinct ()

按需求,直接选一个吧 GROUP: Employees .GroupBy (e => e.JobTitle) .Select ( g => new { JobTitle = g.Key, TotalVacations = g.Sum (e => (Int32)(e.VacationHours)) } ) Distinct: Employees .Select (e => e.JobTitle) .Distinct ()

.问题解决 通过以上分析,将''改为NULL,问题得到有效解决或者把谓词写到每个子SQL里面。当然,只要是非''的都是可以的,比如' '(空格)。 dingjun123@ORADB> SELECT * 2 FROM (SELECT t1.subobject_name, t1.object_name, t1.object_type 3 FRO...

你这个是微软的那个数据库吧 如果要当成返回值的话 定义一个类吧 3个字段的 或者把结果重构成2二维object数组 反正不能直接返回

left outer join=left join , right outer join=right join, inner join=join. 使用关系代数合并数据 1 关系代数 合并数据集合的理论基础是关系代数,它是由E.F.Codd于1970年提出的。 在关系代数的形式化语言中: 用表、或者数据集合表示关系或...

按需求,直接选一个吧 GROUP: Employees .GroupBy (e => e.JobTitle) .Select ( g => new { JobTitle = g.Key, TotalVacations = g.Sum (e => (Int32)(e.VacationHours)) } ) Distinct: Employees .Select (e => e.JobTitle) .Distinct ()

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