Question

OleDbDataAdapter dt = new OleDbDataAdapter("select UserName from UserInfo where User_ID = (select User_ID from Groupmem_info where Group_ID=(select Group_Member_ID from GroupInfo where Group_ID ='" + grp.Text + "'", con);

Can we use this sort of code in access where I need to display user name from three linked tables. Mutual id’s of group and user will be in Group Members Information Table.

Please suggest how to retrieve User name and I want to display all user names in datagridview.

Answer 1

A more efficient approach would be to change the SQL statement to an inner join and use parametrized queries to avoid SQL Injection attacks:

OleDbDataAdapter adapter = new OleDbDataAdapter();
OleDbCommand command;

// Create the SelectCommand.
command = new OleDbCommand("select UserName from UserInfo ui  join Groupmem_info gi on ui.User_ID =ui.User_ID where gi.Group_ID = ? ", con);

command.Parameters.Add("GroupID", OleDbType.Integer);//assuming it's an integer
adapter.SelectCommand = command;

Now you can call Fill on the OleDbDataAdapter and set the DataSource property of the grid to whatever table you filled in:

youGrid.DataSource=yourDataTable;