Performing MERGE with Dapper.net - dapper

Question

We are using Dapper.net for the data layer in an ASP.net MVC 5 app.
One operation requires the use of the MERGE command (if the TitleID exists, update the record, if it doesn't, insert it) - something like this:
MERGE BookInventory bi
USING BookOrder bo
ON bi.TitleID = bo.TitleID
WHEN MATCHED THEN
UPDATE
SET bi.Quantity = bi.Quantity + bo.Quantity
WHEN NOT MATCHED BY TARGET THEN
INSERT (TitleID, Title, Quantity)
VALUES (bo.TitleID, bo.Title,bo.Quantity);
Can Dapper be used to map values onto this MERGE statement?
I can't find anything on this and it's unclear what the best approach to using MERGE with Dapper.net is?

Answer 1

Just found out that you can do it like I did in .NET Fiddle code here: https://dotnetfiddle.net/e2G3Ho
Pasting the code below
// #nuget: Dapper -Version 1.60.6
using Dapper;
using System;
using System.Data.SqlClient;
using System.Linq;
using System.Collections.Generic;
public class Program
{
public class OrderDetail
{
public int OrderDetailID { get; set; }
public int OrderID { get; set; }
public int ProductID { get; set; }
public int Quantity { get; set; }
}
public static void Main()
{
string sql = "SELECT * FROM OrderDetails";
string sql2 = #"MERGE INTO OrderDetails AS TARGET
USING (
VALUES
(#OrderDetailID, #OrderID, #ProductID, #Quantity)
) AS SOURCE (OrderDetailID, OrderID, ProductID, Quantity)
ON SOURCE.OrderDetailID = TARGET.OrderDetailID
WHEN MATCHED THEN
UPDATE SET Quantity = 666
WHEN NOT MATCHED THEN
INSERT (OrderID, ProductID, Quantity)
VALUES (SOURCE.OrderID, SOURCE.ProductID, SOURCE.Quantity);
";
using (var connection = new SqlConnection(FiddleHelper.GetConnectionStringSqlServerW3Schools()))
{
List<OrderDetail> details = new List<OrderDetail> {
{new OrderDetail() {OrderDetailID = 1, OrderID = 1024, ProductID = 42, Quantity = 1000} },
{new OrderDetail() {OrderDetailID = 9999, OrderID = 10268, ProductID = 42, Quantity = 1000} }
};
connection.Execute(sql2, details);
var orderDetails = connection.Query<OrderDetail>(sql).ToList();
FiddleHelper.WriteTable(orderDetails);
}
}
}

Answer 2

Untested, but this should do the trick:
const string sql = #"
merge into SomeTable as Target
using (select #myId AS id) as Source
on (Target.id = Source.id)
when matched then
update set Target.SomeColumn = #myValue
when not matched by Target then
insert (SomeColumn) values (#myValue)";
conn.Execute(sql, new { myId = 999, myValue = 123 })