ExecuteQuery

This method executes a raw SQL statement directly against the database and returns an IEnumerable object. It supports all RDBMS data providers.

Code Snippets

The following example queries all rows from the [dbo].[Person] table.

using (var connection = new SqlConnection(connectionString))
{
    var people = connection.ExecuteQuery<Person>("SELECT * FROM [dbo].[Person];");
}

Returning an enumerable of dynamic objects (typed as ExpandoObject):

using (var connection = new SqlConnection(connectionString))
{
    var dynamicPeople = connection.ExecuteQuery("SELECT * FROM [dbo].[Person];");
}

Returning an enumerable of ExpandoObject:

using (var connection = new SqlConnection(connectionString))
{
    var people = connection.ExecuteQuery<ExpandoObject>("SELECT * FROM [dbo].[Person];");
}

Returning an enumerable of IDictionary<string, object>:

using (var connection = new SqlConnection(connectionString))
{
    var people = connection.ExecuteQuery<IDictionary<string, object>>("SELECT * FROM [dbo].[Person];");
}

An anonymous type can also be passed as the generic type TResult. This is particularly useful in F#.

Typed Result

The result can be inferred as any .NET CLR type.

using (var connection = new SqlConnection(connectionString))
{
    var ids = connection.ExecuteQuery<long>("SELECT Id FROM [dbo].[Person];");
}

Or for other types such as string and System.DateTime:

using (var connection = new SqlConnection(connectionString))
{
    var names = connection.ExecuteQuery<string>("SELECT Name FROM [dbo].[Person];");
    var dateOfBirth = connection.ExecuteQuery<DateTime>("SELECT DateOfBirth FROM [dbo].[Person] WHERE Name = 'John Doe';").FirstOrDefault();
}

Enum types are also supported:

// Enumeration
public enum Gender
{
    Male = 1,
    Female = 2
}

// Inferring
using (var connection = new SqlConnection(connectionString))
{
    var gender = connection.ExecuteQuery<Gender>("SELECT Gender FROM [dbo].[Person] WHERE Name = 'John Doe';").FirstOrDefault();
}

Enumeration inference works for both string column types (e.g., NVARCHAR, TEXT) and non-string column types (e.g., SMALLINT, INT, BIGINT).

Table-Valued Parameters

To execute a Table-Valued Parameter (TVP), create a DataTable and set its name to the name of the User-Defined Type (UDT).

Refer to the Microsoft guidelines for creating a TVP/UDT and calling it from C#/ADO.NET.

var table = new DataTable();
table.TableName = "Name of the UDT";
// Create the 'table' columns/rows

Pass it as an argument value:

using (var connection = new SqlConnection(connectionString))
{
    var tables = connection.ExecuteQuery<IdentityTable>("EXEC [sp_StoredProcedureName] @Table = @Table;",
        new { Table = table })?.AsList();
}

Passing of Parameters

Parameters can be passed via any of the following types:

IDbDataParameter
Anonymous Types
ExpandoObject
IDictionary<string, object>
QueryField/QueryGroup

IDbDataParameter

using (var connection = new SqlConnection(connectionString))
{
    var param = new
    {
        Id = new SqlParameter("_", 10045)
    };
    var person = connection.ExecuteQuery<Person>("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param).FirstOrDefault();
}

The parameter name is not required. The library replaces it with the actual property name from the object.

Anonymous Types

using (var connection = new SqlConnection(connectionString))
{
    var param = new
    {
        Id = 10045
    };
    var person = connection.ExecuteQuery<Person>("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param).FirstOrDefault();
}

ExpandoObject

using (var connection = new SqlConnection(connectionString))
{
    var param = new ExpandoObject() as IDictionary<string, object>;
    param.Add("Id", 10045);
    var person = connection.ExecuteQuery<Person>("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param).FirstOrDefault();
}

IDictionary<string, object>

using (var connection = new SqlConnection(connectionString))
{
    var param = new Dictionary<string, object>
    {
        { "Id", 10045 }
    };
    var person = connection.ExecuteQuery<Person>("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param).FirstOrDefault();
}

QueryField/QueryGroup

using (var connection = new SqlConnection(connectionString))
{
    var param = new []
    {
        new QueryField("Id", 10045)
    };
    var person = connection.ExecuteQuery<Person>("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param).FirstOrDefault();
}

Or via QueryGroup.

using (var connection = new SqlConnection(connectionString))
{
    var param = new QueryGroup(new []
    {
        new QueryField("Id", 10045)
    });
    var person = connection.ExecuteQuery<Person>("SELECT * FROM [dbo].[Person] WHERE Id = @Id;", param).FirstOrDefault();
}

Array Parameters (for the IN keyword)

Pass an array of values when using the IN keyword.

using (var connection = new SqlConnection(connectionString))
{
    var param = new
    {
        Keys = new [] { 10045, 10102, 11004 }
    };
    var people = connection.ExecuteQuery<Person>("SELECT * FROM [dbo].[Person] WHERE Id IN (@Keys);", param);
}

Any of the parameter types listed in Passing of Parameters can also be used here.

Executing a Stored Procedure

There are two ways to execute a stored procedure. Pass the stored procedure name and set the command type to CommandType.StoredProcedure:

using (var connection = new SqlConnection(connectionString))
{
    var person = connection.ExecuteQuery<Person>("[dbo].[sp_GetPerson]",
        new { Id = 10045 }, commandType: CommandType.StoredProcedure).FirstOrDefault();
}

Or use a native SQL EXEC call:

using (var connection = new SqlConnection(connectionString))
{
    var person = connection.ExecuteQuery<Person>("EXEC [dbo].[sp_GetPerson](@Id);",
        new { Id = 10045 }).FirstOrDefault();
}

In the second call, the command text ends with a semicolon and no command type is set.