What can be most efficient way of filtering data in DataTable?

Question

The performance is not good, taking so much time. How can I improve the performance of the following code that gives me the same result?

 

 

for (int i = 0; i < dsResult.Tables[0].Rows.Count; i++)

{

     DataTable dtFiltered = dtWorkExp.Clone();

     foreach (DataRow drr in dtWorkExp.Rows)

     {

          if (drr["UserId"].ToString() == dsResult.Tables[0].Rows[l]["Registration NO."].ToString())

          {

              dtFiltered.ImportRow(drr);

          }

      }

 

 

     DataTable dtFilteredAward= dtAwards.Clone();

     foreach (DataRow drr in dtAwards.Rows)

     {

          if (drr["UserId"].ToString() == dsResult.Tables[0].Rows[l]["Registration NO."].ToString())

          {

              dtFilteredAward.ImportRow(drr);

          }

      }

 

 

     DataTable dtFilteredOtherQual = dtOtherQual.Clone();

     foreach (DataRow drr in dtOtherQual.Rows)

     {

          if (drr["UserId"].ToString() == dsResult.Tables[0].Rows[l]["Registration NO."].ToString())

          {

               dtFilteredOtherQual.ImportRow(drr);

          }

      }

   

     //Do some operation with filtered Data Tables

}