Compare two datasets in C#

Question

i have two datasets and i need to compare these two datasets such that if ID does not exist in one table then i need to write insert Query else update query. For Ex: ``` Id in One dataset ID in second Dataset 1 1 2 2 3 4 ``` I need to insert ID 3 to second dataset. Here is my code for your reference: ``` if (ds.Tables[0].Rows.Count > 0 || clientDS.Tables[0].Rows.Count > 0) { for (int i = 0; i < ds.Tables[0].Rows.Count; i++) { for (int j = 0; j < clientDS.Tables[0].Rows.Count; j++) { if (ds.Tables[0].Rows[i]["Id"].ToString() == clientDS.Tables[0].Rows[j]["Id"].ToString()) { client.GetSingleValue("update customers set Name='" + ds.Tables[0].Rows[i]["Name"].ToString() + "',ContactPerson= '" + ds.Tables[0].Rows[i]["ContactPerson"].ToString() + "',Address='" + ds.Tables[0].Rows[i]["Address"].ToString() + "',TinNo='" + ds.Tables[0].Rows[i]["TinNo"].ToString() + "',ContactNo='" + ds.Tables[0].Rows[i]["Contactno"].ToString() + "',Report= '" + ds.Tables[0].Rows[i]["Report"].ToString() + "',Syn…

Accepted Answer

I think your error is compaing the Id string using `==`. Try using `Equals`. I'd just use a foreach and select instead:

```
foreach (DataRow row in ds.Tables[0].Rows)
{
    string filter = string.Format("Id = '{0}'", row["Id"]);
    DataRow[] rows = clientDS.Tables[0].Select(filter);
    if (rows.length == 0)
    {
        // insert here
    }
    else
    {
        // update here
    }
}
```

Compare two datasets in C#

Solution

Problem