C# 实体框架 fromsqlraw 查询，包含（in）而不是 where 子句

Question

What is the correct syntax for varname to make this query work? I can get it to work with a single variable like

string varname = "TOTAL_NORWAY"

However, if I want to have a few variables in there, I get an empty array returned:

    string varname = "'TOTAL_NORWAY', 'TOTAL_SWEDEN'";
    
   return await _Context.theDataModel.FromSqlRaw(@"
                        select data
                            from data_table 
                            where Variable in ({0})
                            
    
                    ", varname).ToListAsync();

Answer 1

Remember that you can combine FromSqlRaw with Linq:

string varnames = new [] { "TOTAL_NORWAY", "TOTAL_SWEDEN" };

var query = _Context.theDataModel.FromSqlRaw(@"
                        select data
                            from data_table");
    
query = query.Where(x => varnames.Contains(x.Variable));
// Add more where clauses as needed
return await query.ToListAsync();

Answer 2

ErikEJ's post was very helpful. The solution is not so trivial for someone who doesn't dabble in EF Core regularly.

I also had an extra where clause to consider, and this was done like so for anyone else wondering.

var items = new int[] { 1, 2, 3 };

var parameters = new string[items.Length];
var sqlParameters = new List<SqlParameter>();
for (var i = 0; i < items.Length; i++)
{
    parameters[i] = string.Format("@p{0}", i);
    sqlParameters.Add(new SqlParameter(parameters[i], items[i]));
}

sqlParameters.Add(new SqlParameter("@userid", "userXYZ123"));


var rawCommand = string.Format("SELECT * from dbo.Shippers WHERE ShipperId IN ({0}) and userid = {1}", string.Join(", ", parameters), "@userid");

var shipperList = db.Set<ShipperSummary>()
    .FromSqlRaw(rawCommand, sqlParameters.ToArray())
    .ToList();