Get a Maximum Date value from X tables in DataSet












7














I have a DataSet with 1-3 tables, each table have a column named m_date (string)
I want to get max value from all of them using LINQ.



I know how to get each table Maximum value:



var maxDate=ds.Tables[index].AsEnumerable()

              .Max(x=>DateTime.Parse(x["m_date"].ToString())).ToString();


but I don't know how to get Max value from all the tables information



Edit:



I now have something like this which works:



DateTime maxDate=DateTime.MinValue;



foreach  (DataTable tbl in ds.Tables)

{

     DateTime maxDateCur=ds.Tables[index].AsEnumerable()

                  .Max(x=>DateTime.Parse(x["m_date"].ToString()));

     maxDate=new DateTime {maxDateCur,maxDate}.Max();

}


but I have a feeling it could be done better.






c# linq datatable







share|improve this question





























    7














    I have a DataSet with 1-3 tables, each table have a column named m_date (string)
    I want to get max value from all of them using LINQ.



    I know how to get each table Maximum value:



    var maxDate=ds.Tables[index].AsEnumerable()
    
              .Max(x=>DateTime.Parse(x["m_date"].ToString())).ToString();


    but I don't know how to get Max value from all the tables information



    Edit:



    I now have something like this which works:



    DateTime maxDate=DateTime.MinValue;
    

    
foreach  (DataTable tbl in ds.Tables)
    
{
    
     DateTime maxDateCur=ds.Tables[index].AsEnumerable()
    
                  .Max(x=>DateTime.Parse(x["m_date"].ToString()));
    
     maxDate=new DateTime {maxDateCur,maxDate}.Max();
    
}


    but I have a feeling it could be done better.






    c# linq datatable







    share|improve this question



























      7












      7








      7


      1





      I have a DataSet with 1-3 tables, each table have a column named m_date (string)
      I want to get max value from all of them using LINQ.



      I know how to get each table Maximum value:



      var maxDate=ds.Tables[index].AsEnumerable()
      
              .Max(x=>DateTime.Parse(x["m_date"].ToString())).ToString();


      but I don't know how to get Max value from all the tables information



      Edit:



      I now have something like this which works:



      DateTime maxDate=DateTime.MinValue;
      

      
foreach  (DataTable tbl in ds.Tables)
      
{
      
     DateTime maxDateCur=ds.Tables[index].AsEnumerable()
      
                  .Max(x=>DateTime.Parse(x["m_date"].ToString()));
      
     maxDate=new DateTime {maxDateCur,maxDate}.Max();
      
}


      but I have a feeling it could be done better.






      c# linq datatable







      share|improve this question















      I have a DataSet with 1-3 tables, each table have a column named m_date (string)
      I want to get max value from all of them using LINQ.



      I know how to get each table Maximum value:



      var maxDate=ds.Tables[index].AsEnumerable()
      
              .Max(x=>DateTime.Parse(x["m_date"].ToString())).ToString();


      but I don't know how to get Max value from all the tables information



      Edit:



      I now have something like this which works:



      DateTime maxDate=DateTime.MinValue;
      

      
foreach  (DataTable tbl in ds.Tables)
      
{
      
     DateTime maxDateCur=ds.Tables[index].AsEnumerable()
      
                  .Max(x=>DateTime.Parse(x["m_date"].ToString()));
      
     maxDate=new DateTime {maxDateCur,maxDate}.Max();
      
}


      but I have a feeling it could be done better.






      c# linq datatable




      c# linq datatable






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited 16 hours ago









      Uwe Keim

      27.4k30128210




      27.4k30128210










      asked 16 hours ago









      Dor Lugasi

      27214




      27214
























          1 Answer
          1






          active

          oldest

          votes


















          5














          You could do it as:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
        .SelectMany(index => ds.Tables[index].AsEnumerable())
          
        .Max(dataRow => dataRow.Field<DateTime>("m_date"))
          
        .ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses SelectMany to get a single IEnumerable<DataRow>

          • Uses Max to get the maximum value and convert it to a string.


          Slightly different variant would be:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
                .Select(index =>
          
                    ds.Tables[index].AsEnumerable()
          
                        .Max(dataRow => dataRow.Field<DateTime>("m_date")))
          
                .Max().ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses Select to get an IEnumerable<DateTime> consisting of the maximum DateTime of each DataTable

          • Uses Max to get the maximum value of the of the DateTime's and then convert to a string representation.






          share|improve this answer



















          • 1




            Works Great, the only change I made is changing the field to DateTime.ParseExact, because my datetime string is dd/mm/yyyy
            – Dor Lugasi
            15 hours ago










          • and adding .Where(x=>!string.IsNullOrEmpty(x.Field<string>("col_name")))
            – Dor Lugasi
            14 hours ago











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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          5














          You could do it as:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
        .SelectMany(index => ds.Tables[index].AsEnumerable())
          
        .Max(dataRow => dataRow.Field<DateTime>("m_date"))
          
        .ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses SelectMany to get a single IEnumerable<DataRow>

          • Uses Max to get the maximum value and convert it to a string.


          Slightly different variant would be:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
                .Select(index =>
          
                    ds.Tables[index].AsEnumerable()
          
                        .Max(dataRow => dataRow.Field<DateTime>("m_date")))
          
                .Max().ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses Select to get an IEnumerable<DateTime> consisting of the maximum DateTime of each DataTable

          • Uses Max to get the maximum value of the of the DateTime's and then convert to a string representation.






          share|improve this answer



















          • 1




            Works Great, the only change I made is changing the field to DateTime.ParseExact, because my datetime string is dd/mm/yyyy
            – Dor Lugasi
            15 hours ago










          • and adding .Where(x=>!string.IsNullOrEmpty(x.Field<string>("col_name")))
            – Dor Lugasi
            14 hours ago
















          5














          You could do it as:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
        .SelectMany(index => ds.Tables[index].AsEnumerable())
          
        .Max(dataRow => dataRow.Field<DateTime>("m_date"))
          
        .ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses SelectMany to get a single IEnumerable<DataRow>

          • Uses Max to get the maximum value and convert it to a string.


          Slightly different variant would be:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
                .Select(index =>
          
                    ds.Tables[index].AsEnumerable()
          
                        .Max(dataRow => dataRow.Field<DateTime>("m_date")))
          
                .Max().ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses Select to get an IEnumerable<DateTime> consisting of the maximum DateTime of each DataTable

          • Uses Max to get the maximum value of the of the DateTime's and then convert to a string representation.






          share|improve this answer



















          • 1




            Works Great, the only change I made is changing the field to DateTime.ParseExact, because my datetime string is dd/mm/yyyy
            – Dor Lugasi
            15 hours ago










          • and adding .Where(x=>!string.IsNullOrEmpty(x.Field<string>("col_name")))
            – Dor Lugasi
            14 hours ago














          5












          5








          5






          You could do it as:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
        .SelectMany(index => ds.Tables[index].AsEnumerable())
          
        .Max(dataRow => dataRow.Field<DateTime>("m_date"))
          
        .ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses SelectMany to get a single IEnumerable<DataRow>

          • Uses Max to get the maximum value and convert it to a string.


          Slightly different variant would be:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
                .Select(index =>
          
                    ds.Tables[index].AsEnumerable()
          
                        .Max(dataRow => dataRow.Field<DateTime>("m_date")))
          
                .Max().ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses Select to get an IEnumerable<DateTime> consisting of the maximum DateTime of each DataTable

          • Uses Max to get the maximum value of the of the DateTime's and then convert to a string representation.






          share|improve this answer














          You could do it as:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
        .SelectMany(index => ds.Tables[index].AsEnumerable())
          
        .Max(dataRow => dataRow.Field<DateTime>("m_date"))
          
        .ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses SelectMany to get a single IEnumerable<DataRow>

          • Uses Max to get the maximum value and convert it to a string.


          Slightly different variant would be:



          var maxDate = Enumerable.Range(0, ds.Tables.Count)
          
                .Select(index =>
          
                    ds.Tables[index].AsEnumerable()
          
                        .Max(dataRow => dataRow.Field<DateTime>("m_date")))
          
                .Max().ToString();



          • Uses Enumerable.Range to generate the indices enabling us to access each individual DataTable.

          • Uses Select to get an IEnumerable<DateTime> consisting of the maximum DateTime of each DataTable

          • Uses Max to get the maximum value of the of the DateTime's and then convert to a string representation.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited 15 hours ago

























          answered 16 hours ago









          Aomine

          39k73366




          39k73366








          • 1




            Works Great, the only change I made is changing the field to DateTime.ParseExact, because my datetime string is dd/mm/yyyy
            – Dor Lugasi
            15 hours ago










          • and adding .Where(x=>!string.IsNullOrEmpty(x.Field<string>("col_name")))
            – Dor Lugasi
            14 hours ago














          • 1




            Works Great, the only change I made is changing the field to DateTime.ParseExact, because my datetime string is dd/mm/yyyy
            – Dor Lugasi
            15 hours ago










          • and adding .Where(x=>!string.IsNullOrEmpty(x.Field<string>("col_name")))
            – Dor Lugasi
            14 hours ago








          1




          1




          Works Great, the only change I made is changing the field to DateTime.ParseExact, because my datetime string is dd/mm/yyyy
          – Dor Lugasi
          15 hours ago




          Works Great, the only change I made is changing the field to DateTime.ParseExact, because my datetime string is dd/mm/yyyy
          – Dor Lugasi
          15 hours ago












          and adding .Where(x=>!string.IsNullOrEmpty(x.Field<string>("col_name")))
          – Dor Lugasi
          14 hours ago




          and adding .Where(x=>!string.IsNullOrEmpty(x.Field<string>("col_name")))
          – Dor Lugasi
          14 hours ago


















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