title: How to merge two datatables in c# (without any common identifier)?8
body: <p>I am trying to merge two data table dt and dt4. I want to merge 2 data tables, having different schemas, and no common identifier together. Becuase the first data table dt contains some values.I get dt count on x. Based on that count I have to fetch some value table and stored in dt4. if if dt contains 3 row value then x=3 and dt4 contains 3 values. After these process I have to merge dt and dt4 and displayed as one table. 
  While using the given below code getting one error. The error is : <code>"'column' argument cannot be null."</code> Help me to find a proper soluion. Thank you.</p>
  
  <p>Code:</p>
  
  <pre><code>protected void ddlCircle_SelectedIndexChanged(object sender, EventArgs e)
  {
      ShadingAnalysisDataSetTableAdapters.tbl_CadEngineersTeamTableAdapter cd;
      cd = new ShadingAnalysisDataSetTableAdapters.tbl_CadEngineersTeamTableAdapter();
      DataTable dt = new DataTable();
      dt = cd.GetAvailableData(ddlCircle.SelectedValue); // Getting details of unassigned site
  
      int x, y;
  
      DataTable dt3 = new DataTable();
      dt3 = cd.GetTeam();
      y = dt3.Rows.Count;
  
      x = dt.Rows.Count; // counting the unassinged sites
  
      DataTable dt2 = new DataTable();
      dt2 = cd.GetAssignTeam(x);           //Getting team based on count
  
      string[] arr = new string[dt2.Rows.Count];
      int i = 0;
      foreach (DataRow r in dt2.Rows)
      {
          arr[i] = r["Team"].ToString(); // assigning available team to array
          i++;
      }
  
      string[] strArr = new string[x+1]; // another array to copy arr values.
  
      i = 0; int j = 0;
      while (j &lt;= x)
      {
          strArr[j]=  arr[i] ; // copying the arr[] values into strArr[] based on count.
          i++;
          j++;
  
          if (i == y)
          {
              i = 0;
          }
      }
       DataTable dt4 = new DataTable();
       dt4.Columns.Add("Team");
  
       foreach (string s in strArr)
         {
            dt4.Rows.Add(s); // Converting string array strArr[] to data table dt4
          }
  
       dt.Merge(dt4);  // error poppup here. Error : 'column' argument cannot be null.
       GridView2.DataSource = dt;
       GridView2.DataBind();
  }
  </code></pre>
  
  <p>dt contain</p>
  
  <pre><code>State  District  SiteID  SiteName
  -----  --------  ------  --------
  Sate1  District1  1001     A
  Sate2  District2  1002     B
  Sate3  District3  1003     C
  </code></pre>
  
  <p>dt4 contain</p>
  
  <pre><code>Team
  -----
  Team1
  Team2
  Team3
  </code></pre>
  
  <p>I need a final output as:</p>
  
  <pre><code>State  District  SiteID  SiteName  Team
  -----  --------  ------  --------  -----
  Sate1  District1  1001     A       Team1
  Sate2  District2  1002     B       Team2
  Sate3  District3  1003     C       Team3
  </code></pre>