哪个网站教做饭做的好,成都建网站,长沙关键词排名软件,在putty做网站要拷贝什么文章目录 C#两个表多条件关联写法两个表实体类准备实体类数据初始化第一种 sql的左关联第二种相当于sql的 INNER JOIN写法一#xff1a;FROM a FROM b where 多条件关联写法二#xff1a; FROM JOIN INTO写法三#xff1a; FROM JOIN 省略into C#两个表多条件关联写法
两个… 文章目录 C#两个表多条件关联写法两个表实体类准备实体类数据初始化第一种 sql的左关联第二种相当于sql的 INNER JOIN写法一FROM a FROM b where 多条件关联写法二 FROM JOIN INTO写法三 FROM JOIN 省略into C#两个表多条件关联写法
两个表实体类准备 public class OtherIn{public string AfterOrderNo { get; set; }public long MaterialId { get; set; }public string MaterNumber { get; set; }public long Qty { get; set; }public string Note { get; set; }}public class AfterInfo{public string AfterOrderNo { get; set; }public long MaterialId { get; set; }public string MaterNumber { get; set; }public long AfterQty { get; set; }public string Note { get; set; }}实体类数据初始化
ListOtherIn getOtherInGroup new ListOtherIn();getOtherInGroup.Add(new OtherIn { AfterOrderNo SH231025001,MaterialId100001,MaterNumberCTG001,Qty2});getOtherInGroup.Add(new OtherIn{AfterOrderNo SH231025001,MaterialId 100002,MaterNumber CTG002,Qty 3});getOtherInGroup.Add(new OtherIn{AfterOrderNo SH231025002,MaterialId 100002,MaterNumber CTG002,Qty 4});ListAfterInfo getAfterGroup new ListAfterInfo();getAfterGroup.Add(new AfterInfo {AfterOrderNo SH231025002,MaterialId 100002,MaterNumber CTG002,AfterQty 5});getAfterGroup.Add(new AfterInfo{AfterOrderNo SH231025001,MaterialId 100001,MaterNumber CTG001,AfterQty 1});第一种 sql的左关联
FROM a JOIN b on 组合键关联 into 临时表 from 临时表左关联不上右边默认为空 var getExcessGroup from a in getOtherInGroupjoin b in getAfterGroup on new { a.AfterOrderNo, a.MaterialId } equals new { b.AfterOrderNo,b.MaterialId }into resultfrom c in result.DefaultIfEmpty()select new{AfterOrderNo a.AfterOrderNo,MaterialIda.MaterialId,Qty a.Qty,AfterQty c null ? 0 : c.AfterQty};结果
第二种相当于sql的 INNER JOIN
写法一FROM a FROM b where 多条件关联 var getExcessGroup2 from a in getOtherInGroupfrom b in getAfterGroupwhere a.AfterOrderNo b.AfterOrderNo a.MaterialId b.MaterialIdselect new{AfterOrderNo a.AfterOrderNo,MaterialId a.MaterialId,Qty a.Qty,AfterQty b null ? 0 : b.AfterQty};结果
写法二 FROM JOIN INTO
FROM a JOIN b on 组合键关联 into 临时表 from 临时表不默认为空
var getExcessGroup1 from a in getOtherInGroupjoin b in getAfterGroup on new { a.AfterOrderNo, a.MaterialId } equals new { b.AfterOrderNo, b.MaterialId }into resultfrom c in resultselect new{AfterOrderNo a.AfterOrderNo,MaterialId a.MaterialId,Qty a.Qty,AfterQty c null ? 0 : c.AfterQty};结果
写法三 FROM JOIN 省略into
var getExcessGroup11 from a in getOtherInGroupjoin b in getAfterGroup on new { a.AfterOrderNo, a.MaterialId } equals new { b.AfterOrderNo, b.MaterialId }select new{AfterOrderNo a.AfterOrderNo,MaterialId a.MaterialId,Qty a.Qty,AfterQty b.AfterQty};结果
