ExecuteNonQuery returning -1 when using sql COUNT despite the query string

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粉色の甜心
粉色の甜心 2020-11-29 12:55

For some reason, ExecuteNonQuery() in C# returns -1, though when I run a query separately, the value returns the actual value needed.

For E

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  • 2020-11-29 13:12

    Based on MSDN:

    For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command. When a trigger exists on a table being inserted or updated, the return value includes the number of rows affected by both the insert or update operation and the number of rows affected by the trigger or triggers. For all other types of statements, the return value is -1. If a rollback occurs, the return value is also -1.

    You want to return the number of rows affected by the command and save it to an int variable but since the type of statement is select so it returns -1.

    Solution: If you want to get the number of rows affected by the SELECT command and save it to an int variable you can use ExecuteScalar.

    var theCount = (int)cmd.ExecuteScalar();
    
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  • 2020-11-29 13:25

    You can use Ef core with Ado.net like this example

    var context = new SampleDbContext();
    using (var connection = context.Database.GetDbConnection())
    {
        connection.Open();
    
        using (var command = connection.CreateCommand())
        {
            command.CommandText = "SELECT COUNT(*) FROM SomeTable";
            var result = command.ExecuteScalar().ToString();
        }
    }
    
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