What is the simplest and most efficient way to find if a data returns using a query? I'm using DataTable
like sqlAdapter.Fill(_table1)
and then doing _table1.Rows.Count
to see if a datatable has any rows. Is there any classes and functions in C# that just gives me if there are any rows. I don't need the data of the rows. Just the count is what I need. I'm running this query against very large datasets so I don't wanna fill the datatable with all the row info.
string myScalarQuery = "select count(*) from TableName";
SqlCommand myCommand = new SqlCommand(myScalarQuery, myConnection);
myCommand.Connection.Open();
int count = (int) myCommand.ExecuteScalar();
myConnection.Close();
Possible optimization of the query per the comments bellow: Select Top 1 * FROM TableName
The least expensive way is using SqlDataReader's HasRows property
UPDATE : of course, the most efficient SELECT query will be like "Select Top 1 1 FROM TableName", which doesn't even need to pull any column data.
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
using (SqlDataReader rdr = cmd.ExecuteReader())
{
if (rdr.HasRows)
...
}
}
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