Getting distinct fields from a dataset

[Mike9900]

Hello,

I have this data in a DataSet:

Year Account Amount

1995 1 999
1995 2 323
1995 3 321
1996 1 354
1996 2 434

I want to get the distinct number if years, in this instance 1995 and 1996
in one query. Is it possible please? Please note that the data is in a
DataSet, I can loop and use HashTable, but this is not a good way.
--
Mike

[Peter Bromberg [C# MVP]]

Mike,
I believe this may be the sixth time I've seen this one in the last couple
of months!

Aside from jumping through programmatic hoops (such as with a Hashtable,
etc) the easiest way is to ensure your rows are distinct on the database side
with "SELECT DISTINCT"
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Mike9900" wrote:

Hello,

I have this data in a DataSet:

Year Account Amount

1995 1 999
1995 2 323
1995 3 321
1996 1 354
1996 2 434

I want to get the distinct number if years, in this instance 1995 and 1996
in one query. Is it possible please? Please note that the data is in a
DataSet, I can loop and use HashTable, but this is not a good way.
--
Mike

[Mike9900]

Hello,

Thanks for the reply.

This is the best idea, but we need this data without distinct. But when it
is in the client, we need it this way.
--
Mike
"Peter Bromberg [C# MVP]" wrote:

Mike,
I believe this may be the sixth time I've seen this one in the last couple
of months!

Aside from jumping through programmatic hoops (such as with a Hashtable,
etc) the easiest way is to ensure your rows are distinct on the database side
with "SELECT DISTINCT"
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Mike9900" wrote:

Hello,

I have this data in a DataSet:

Year Account Amount

1995 1 999
1995 2 323
1995 3 321
1996 1 354
1996 2 434

I want to get the distinct number if years, in this instance 1995 and 1996
in one query. Is it possible please? Please note that the data is in a
DataSet, I can loop and use HashTable, but this is not a good way.
--
Mike

[krispi]

You can create a Command object (OleDb or SQL) that has a CommandText property set to SELECT DISTINCT statement. Then you should execute DataReader to get desired data. Here’s an example how can you fill a ComboBox with distinct data (but in this case you must open a connection, it's not from dataset):

System.Data.OleDb.OleDbCommand cmdDistinct = new System.Data.OleDb.OleDbCommand();
 
cmdDistinct.CommandText = "SELECT DISTINCT DesiredColumn FROM DesiredTable";
cmdDistinct.Connection = myOleDbConnection;
 
myOleDbConnection.Open();
System.Data.OleDb.OleDbDataReader rdr = cmdDistinct.ExecuteReader();
 
while(rdr.Read())
{
    myCombo.Items.Add(rdr.GetValue(0).ToString());
 
    // or like this:
    // myCombo.Items.Add(rdr["DesiredColumn"].ToString());
}
 
rdr.Close();
myOleDbConnection.Close();

Hello,

Thanks for the reply.

This is the best idea, but we need this data without distinct. But when it
is in the client, we need it this way.
--
Mike

[Peter Bromberg [C# MVP]]

Of course, you could always return a DataSet containing one table with
"distinct" and the other one for whatever reason you have to have it that way.
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Mike9900" wrote:

Hello,

Thanks for the reply.

This is the best idea, but we need this data without distinct. But when it
is in the client, we need it this way.
--
Mike
"Peter Bromberg [C# MVP]" wrote:

Mike,
I believe this may be the sixth time I've seen this one in the last couple
of months!

Aside from jumping through programmatic hoops (such as with a Hashtable,
etc) the easiest way is to ensure your rows are distinct on the database side
with "SELECT DISTINCT"
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Mike9900" wrote:

Hello,

I have this data in a DataSet:

Year Account Amount

1995 1 999
1995 2 323
1995 3 321
1996 1 354
1996 2 434

I want to get the distinct number if years, in this instance 1995 and 1996
in one query. Is it possible please? Please note that the data is in a
DataSet, I can loop and use HashTable, but this is not a good way.
--
Mike

[Greg Young]

If you wish to do it without a seperate query to the database, there is a
full helper routine here
http://support.microsoft.com/default...b;en-us;326176

Cheers,

Greg Young
MVP - C#
http://codebetter.com/blogs/gregyoung

"Mike9900" <Mi******@discu ssions.microsof t.com> wrote in message
news:2A******** *************** ***********@mic rosoft.com...

Hello,

I have this data in a DataSet:

Year Account Amount

1995 1 999
1995 2 323
1995 3 321
1996 1 354
1996 2 434

I want to get the distinct number if years, in this instance 1995 and 1996
in one query. Is it possible please? Please note that the data is in a
DataSet, I can loop and use HashTable, but this is not a good way.
--
Mike