sql-server-samples/samples/features/json/azure-function-rest-api/azure-function/run.csx

using System.Net;
using System.Configuration;
using Belgrade.SqlClient;
using Belgrade.SqlClient.SqlDb;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    log.Info("C# HTTP trigger function processed a request.");

    try{
        string ConnectionString = ConfigurationManager.ConnectionStrings["azure-db-connection"].ConnectionString;
        
        var httpStatus = HttpStatusCode.OK;
        string body = 
            await (new QueryMapper(ConnectionString)
                        .OnError(ex => { httpStatus = HttpStatusCode.InternalServerError; }))
            .GetStringAsync("select * from sys.objects for json path");
        return new HttpResponseMessage() { Content = new StringContent(body), StatusCode = httpStatus };

    } catch (Exception ex) {
        log.Error($"C# Http trigger function exception: {ex.Message}");
        return new HttpResponseMessage() { Content = new StringContent(""), StatusCode = HttpStatusCode.InternalServerError };
    }
}