Check if record exists with Dapper ORM

Question

What is the simplest way to check if record exists using the Dapper ORM?

Do I really need to define POCO objects for a query where I only want to check if a record exists?

Answer 1

int id = ...
var exists = conn.ExecuteScalar<bool>("select count(1) from Table where Id=@id", new {id});

should work...

Answer 2

I think this may have a tad less overhead as there's no function call or data type conversions:

int id = ...
var exists = connection.Query<object>(
    "SELECT 1 WHERE EXISTS (SELECT 1 FROM MyTable WHERE ID = @id)", new { id })
    .Any();

Answer 3

const string sql = "SELECT CAST(CASE WHEN EXISTS (SELECT 1 FROM MyTable WHERE Id = @Id) THEN 1 ELSE 0 END as BIT)";
bool exists = db.ExecuteScalar<bool>(sql, new { Id = 123 });