Question

I have this simple C# code which is used by Sql Server to return TVF:

[SqlFunction(FillRowMethodName = "FillRow3")]
public static IEnumerable GetCsv(string csv)
{
    string[] arr = csv.Split(',');
    return arr;
}

public static void FillRow3(Object obj, out int val, out int index)
{
    val = int.Parse((string)obj) ;
    index =  ??? <----------?
}

Hoever – I want to return a table which has 2 columns : ( val,index)

How can I return for each row , its index ( 0-based) according to arr

(obj is the row from arr.)

p.s –
I can create an array of MyItem which will contain [value,index] in the GetCsv method.
And then – obj row ( val+index) will be visible to FillRow3 method.
But I don’t want to do that.

Answer 1

It should look like this:

[SqlFunction(FillRowMethodName = "FillRow3")]
public static IEnumerable GetCsv(string csv)
{
    string[] arr = csv.Split(',');
    return arr.Select((x, i) => Tuple.Create(x, i));
}

public static void FillRow3(Object obj, out string val, out int index)
{
    var input = (Tuple<string, int>)obj;
    val = input.Item1;
    index = input.Item2;
}

Notice, that no static variables are needed. If you don’t think static state inside of SQL Server is a problem please research this issue.