Inner Join with two equalities inside on clause in LINQ Lambda





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I'm trying to convert a Sql query to a Linq Lambda style query. Thought this would be something easy but it turned out not.



SQL Query is as follows;



select distinct t1.ID from table1 t1
inner Join table2 t2on (t2.FromId= t1.Id or t2.ToId= t1.Id)
where t1.TenantId = 12
and t2.wId= 51


All examples I came across are for one clause joins so far. I wrote something like this



    actStaList = _db.t1
.Join(_db.t2,
s => s.ID,
wf => wf.ToId,
(s, wf) => new { t1= s, t2= wf }
)
.Where(a => a.t1.Tenant.Guid == _tenantGuid)
.Select (m=>m.t1.ID)
.ToList();


It is obvious this won't work as the sql query above but still it's a start.
Still I can't figure where should I add the second part inside INNER JOIN and Distinct keyword.










share|improve this question































    1















    I'm trying to convert a Sql query to a Linq Lambda style query. Thought this would be something easy but it turned out not.



    SQL Query is as follows;



    select distinct t1.ID from table1 t1
    inner Join table2 t2on (t2.FromId= t1.Id or t2.ToId= t1.Id)
    where t1.TenantId = 12
    and t2.wId= 51


    All examples I came across are for one clause joins so far. I wrote something like this



        actStaList = _db.t1
    .Join(_db.t2,
    s => s.ID,
    wf => wf.ToId,
    (s, wf) => new { t1= s, t2= wf }
    )
    .Where(a => a.t1.Tenant.Guid == _tenantGuid)
    .Select (m=>m.t1.ID)
    .ToList();


    It is obvious this won't work as the sql query above but still it's a start.
    Still I can't figure where should I add the second part inside INNER JOIN and Distinct keyword.










    share|improve this question



























      1












      1








      1








      I'm trying to convert a Sql query to a Linq Lambda style query. Thought this would be something easy but it turned out not.



      SQL Query is as follows;



      select distinct t1.ID from table1 t1
      inner Join table2 t2on (t2.FromId= t1.Id or t2.ToId= t1.Id)
      where t1.TenantId = 12
      and t2.wId= 51


      All examples I came across are for one clause joins so far. I wrote something like this



          actStaList = _db.t1
      .Join(_db.t2,
      s => s.ID,
      wf => wf.ToId,
      (s, wf) => new { t1= s, t2= wf }
      )
      .Where(a => a.t1.Tenant.Guid == _tenantGuid)
      .Select (m=>m.t1.ID)
      .ToList();


      It is obvious this won't work as the sql query above but still it's a start.
      Still I can't figure where should I add the second part inside INNER JOIN and Distinct keyword.










      share|improve this question
















      I'm trying to convert a Sql query to a Linq Lambda style query. Thought this would be something easy but it turned out not.



      SQL Query is as follows;



      select distinct t1.ID from table1 t1
      inner Join table2 t2on (t2.FromId= t1.Id or t2.ToId= t1.Id)
      where t1.TenantId = 12
      and t2.wId= 51


      All examples I came across are for one clause joins so far. I wrote something like this



          actStaList = _db.t1
      .Join(_db.t2,
      s => s.ID,
      wf => wf.ToId,
      (s, wf) => new { t1= s, t2= wf }
      )
      .Where(a => a.t1.Tenant.Guid == _tenantGuid)
      .Select (m=>m.t1.ID)
      .ToList();


      It is obvious this won't work as the sql query above but still it's a start.
      Still I can't figure where should I add the second part inside INNER JOIN and Distinct keyword.







      linq lambda






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Jan 3 at 9:42









      piet.t

      10.1k73246




      10.1k73246










      asked Jan 3 at 9:20









      Ege BayrakEge Bayrak

      425825




      425825
























          2 Answers
          2






          active

          oldest

          votes


















          2














          One option you have is to use two separate Linq Queries and concat the result(and eliminating duplicates).



           var left = t1.Join(t2,
          s => s.ID,
          wf => wf.ToId,
          (s, wf) => new { t1= s, t2= wf }
          ).Select(x=>x);

          var right = t1.Join(t2,
          s => s.ID,
          wf => wf.FromId,
          (s, wf) => new { t1= s, t2= wf }
          ).Select(x=>x);

          var actStaList = left.Concat(right).Select(m=>m.t1.ID)
          .Distinct();


          Please note I have omitted the Where Clause in the example as in the OP, both Sql version and your attempted Linq version seem to have different conditions. You can add them yourself.






          share|improve this answer


























          • Where clause is easy to add so I left it out for sake of simplicity, thanks for the heads up.

            – Ege Bayrak
            Jan 3 at 9:39











          • Note that you can do left.Union(right) and remove .Distinct() because UNION is an implicit DISTINCT.

            – Gert Arnold
            Jan 3 at 14:28



















          1














          The LINQ Join statement only supports equi-joins. For other types of equality you can't use the Join statement and have to code the equality manually. This is much easier in query syntax:



          actStaList = (
          from t1 in _db.table1
          from t2 in _db.table2
          where t2.FromId == t1.Id || t2.ToId == t1.Id
          where t1.TenantId == 12 && t2.wId == 51
          select t1.ID
          ).Distinct();


          For the record, you can avoid the Distinct statement by executing this as a SQL EXISTS statement:



          actStaList =
          from t1 in _db.table1
          where t1.TenantId == 12
          where (from t2 in _db.table2
          where t2.wId == 51 && (t2.FromId == t1.Id || t2.ToId == t1.Id)
          select t2).Any()
          select t1.ID;





          share|improve this answer
























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            2 Answers
            2






            active

            oldest

            votes








            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2














            One option you have is to use two separate Linq Queries and concat the result(and eliminating duplicates).



             var left = t1.Join(t2,
            s => s.ID,
            wf => wf.ToId,
            (s, wf) => new { t1= s, t2= wf }
            ).Select(x=>x);

            var right = t1.Join(t2,
            s => s.ID,
            wf => wf.FromId,
            (s, wf) => new { t1= s, t2= wf }
            ).Select(x=>x);

            var actStaList = left.Concat(right).Select(m=>m.t1.ID)
            .Distinct();


            Please note I have omitted the Where Clause in the example as in the OP, both Sql version and your attempted Linq version seem to have different conditions. You can add them yourself.






            share|improve this answer


























            • Where clause is easy to add so I left it out for sake of simplicity, thanks for the heads up.

              – Ege Bayrak
              Jan 3 at 9:39











            • Note that you can do left.Union(right) and remove .Distinct() because UNION is an implicit DISTINCT.

              – Gert Arnold
              Jan 3 at 14:28
















            2














            One option you have is to use two separate Linq Queries and concat the result(and eliminating duplicates).



             var left = t1.Join(t2,
            s => s.ID,
            wf => wf.ToId,
            (s, wf) => new { t1= s, t2= wf }
            ).Select(x=>x);

            var right = t1.Join(t2,
            s => s.ID,
            wf => wf.FromId,
            (s, wf) => new { t1= s, t2= wf }
            ).Select(x=>x);

            var actStaList = left.Concat(right).Select(m=>m.t1.ID)
            .Distinct();


            Please note I have omitted the Where Clause in the example as in the OP, both Sql version and your attempted Linq version seem to have different conditions. You can add them yourself.






            share|improve this answer


























            • Where clause is easy to add so I left it out for sake of simplicity, thanks for the heads up.

              – Ege Bayrak
              Jan 3 at 9:39











            • Note that you can do left.Union(right) and remove .Distinct() because UNION is an implicit DISTINCT.

              – Gert Arnold
              Jan 3 at 14:28














            2












            2








            2







            One option you have is to use two separate Linq Queries and concat the result(and eliminating duplicates).



             var left = t1.Join(t2,
            s => s.ID,
            wf => wf.ToId,
            (s, wf) => new { t1= s, t2= wf }
            ).Select(x=>x);

            var right = t1.Join(t2,
            s => s.ID,
            wf => wf.FromId,
            (s, wf) => new { t1= s, t2= wf }
            ).Select(x=>x);

            var actStaList = left.Concat(right).Select(m=>m.t1.ID)
            .Distinct();


            Please note I have omitted the Where Clause in the example as in the OP, both Sql version and your attempted Linq version seem to have different conditions. You can add them yourself.






            share|improve this answer















            One option you have is to use two separate Linq Queries and concat the result(and eliminating duplicates).



             var left = t1.Join(t2,
            s => s.ID,
            wf => wf.ToId,
            (s, wf) => new { t1= s, t2= wf }
            ).Select(x=>x);

            var right = t1.Join(t2,
            s => s.ID,
            wf => wf.FromId,
            (s, wf) => new { t1= s, t2= wf }
            ).Select(x=>x);

            var actStaList = left.Concat(right).Select(m=>m.t1.ID)
            .Distinct();


            Please note I have omitted the Where Clause in the example as in the OP, both Sql version and your attempted Linq version seem to have different conditions. You can add them yourself.







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited Jan 3 at 9:39

























            answered Jan 3 at 9:38









            Anu ViswanAnu Viswan

            6,0792526




            6,0792526













            • Where clause is easy to add so I left it out for sake of simplicity, thanks for the heads up.

              – Ege Bayrak
              Jan 3 at 9:39











            • Note that you can do left.Union(right) and remove .Distinct() because UNION is an implicit DISTINCT.

              – Gert Arnold
              Jan 3 at 14:28



















            • Where clause is easy to add so I left it out for sake of simplicity, thanks for the heads up.

              – Ege Bayrak
              Jan 3 at 9:39











            • Note that you can do left.Union(right) and remove .Distinct() because UNION is an implicit DISTINCT.

              – Gert Arnold
              Jan 3 at 14:28

















            Where clause is easy to add so I left it out for sake of simplicity, thanks for the heads up.

            – Ege Bayrak
            Jan 3 at 9:39





            Where clause is easy to add so I left it out for sake of simplicity, thanks for the heads up.

            – Ege Bayrak
            Jan 3 at 9:39













            Note that you can do left.Union(right) and remove .Distinct() because UNION is an implicit DISTINCT.

            – Gert Arnold
            Jan 3 at 14:28





            Note that you can do left.Union(right) and remove .Distinct() because UNION is an implicit DISTINCT.

            – Gert Arnold
            Jan 3 at 14:28













            1














            The LINQ Join statement only supports equi-joins. For other types of equality you can't use the Join statement and have to code the equality manually. This is much easier in query syntax:



            actStaList = (
            from t1 in _db.table1
            from t2 in _db.table2
            where t2.FromId == t1.Id || t2.ToId == t1.Id
            where t1.TenantId == 12 && t2.wId == 51
            select t1.ID
            ).Distinct();


            For the record, you can avoid the Distinct statement by executing this as a SQL EXISTS statement:



            actStaList =
            from t1 in _db.table1
            where t1.TenantId == 12
            where (from t2 in _db.table2
            where t2.wId == 51 && (t2.FromId == t1.Id || t2.ToId == t1.Id)
            select t2).Any()
            select t1.ID;





            share|improve this answer




























              1














              The LINQ Join statement only supports equi-joins. For other types of equality you can't use the Join statement and have to code the equality manually. This is much easier in query syntax:



              actStaList = (
              from t1 in _db.table1
              from t2 in _db.table2
              where t2.FromId == t1.Id || t2.ToId == t1.Id
              where t1.TenantId == 12 && t2.wId == 51
              select t1.ID
              ).Distinct();


              For the record, you can avoid the Distinct statement by executing this as a SQL EXISTS statement:



              actStaList =
              from t1 in _db.table1
              where t1.TenantId == 12
              where (from t2 in _db.table2
              where t2.wId == 51 && (t2.FromId == t1.Id || t2.ToId == t1.Id)
              select t2).Any()
              select t1.ID;





              share|improve this answer


























                1












                1








                1







                The LINQ Join statement only supports equi-joins. For other types of equality you can't use the Join statement and have to code the equality manually. This is much easier in query syntax:



                actStaList = (
                from t1 in _db.table1
                from t2 in _db.table2
                where t2.FromId == t1.Id || t2.ToId == t1.Id
                where t1.TenantId == 12 && t2.wId == 51
                select t1.ID
                ).Distinct();


                For the record, you can avoid the Distinct statement by executing this as a SQL EXISTS statement:



                actStaList =
                from t1 in _db.table1
                where t1.TenantId == 12
                where (from t2 in _db.table2
                where t2.wId == 51 && (t2.FromId == t1.Id || t2.ToId == t1.Id)
                select t2).Any()
                select t1.ID;





                share|improve this answer













                The LINQ Join statement only supports equi-joins. For other types of equality you can't use the Join statement and have to code the equality manually. This is much easier in query syntax:



                actStaList = (
                from t1 in _db.table1
                from t2 in _db.table2
                where t2.FromId == t1.Id || t2.ToId == t1.Id
                where t1.TenantId == 12 && t2.wId == 51
                select t1.ID
                ).Distinct();


                For the record, you can avoid the Distinct statement by executing this as a SQL EXISTS statement:



                actStaList =
                from t1 in _db.table1
                where t1.TenantId == 12
                where (from t2 in _db.table2
                where t2.wId == 51 && (t2.FromId == t1.Id || t2.ToId == t1.Id)
                select t2).Any()
                select t1.ID;






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Jan 3 at 10:29









                Gert ArnoldGert Arnold

                79.9k17141205




                79.9k17141205






























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