I have a Windows Forms application and a SQL Server Compact 3.5 database. I want to store in a variable the number of rows from a table where a column has a certain value. I have something like this to count all the rows from a table:
CarsDataSet carsData = new CarsDataSet();
int nrCars = carsData.CarName.Rows.Count;
How can I get the information I need?
First you'll want to write your SQL command which returns the number of rows in the query (using the count(*) operator). The where clause of the SQL statement is where you can filter what specific Cars you want (eg Model = 'Ford')
string sql = "select count(*) from Cars where SomeColumn='{put_your_filter_here}'";
Now create a SqlCommand object which we will execute on your SqlCeConnection. You'll need to open a SqlCeConnection to your local Sql Compact Edition database.
SqlCeCommand cmd = new SqlCeCommand(sql, DbConnection.ceConnection);
Execute the command which returns the count(*) number of rows and stores in cars variable
int cars = (int)cmd.ExecuteScalar();
Use/print the result of the query
Console.WriteLine("Number of cars: " + cars);
您可以像这样获得它。
dcarsData.CarName.Rows.Select("CompanyName Like 'SomeString%'").Count()
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