C# - applySQL. "Select sum()......"

Hello colleagues, I have a problem. I'm trying to do a SQL, select sum(.....). The code doesn't give me an error, but I don't know how to access the value of the variable later.

If you see my code, I have assigned a name to the value received, but when I execute the code, it always gives me "0", which is the value I have entered if there is nothing.

Innovator innovator = this.getInnovator();

// var innovator = new Innovator();

string ID = this.getID();

// esto sumaria todas las etapas
var SentenciaSql = " select sum(MT_R_RUT_ETA.mt_rp_rut_eta_ltime) as 'Resultado'"+
" from innovator.MT_RUTA "+
" join innovator.MT_R_RUT_ETA on MT_RUTA.id = MT_R_RUT_ETA.SOURCE_ID "+
" where MT_RUTA.id = '"+ID+"'";

var ResultadoSQL = innovator.applySQL(SentenciaSql);

// tomamos el valor de la suma
var LT_Tot = ResultadoSQL.getProperty("Resultado","0");

// esto sumaria todas las etapas MENOS APROVISIONAMIENTO
SentenciaSql = " select sum(MT_R_RUT_ETA.mt_rp_rut_eta_ltime) as 'Resultado'"+
" from innovator.MT_RUTA "+
" join innovator.MT_R_RUT_ETA on MT_RUTA.id = MT_R_RUT_ETA.SOURCE_ID "+
" where MT_RUTA.id = '"+ID+"' and MT_R_RUT_ETA.KEYED_NAME not like 'APROV%'";

ResultadoSQL = innovator.applySQL(SentenciaSql);

// tomamos el valor de la suma
var LT_Par = ResultadoSQL.getProperty("Resultado","0");

//String s = LT_Tot.ToString() + " - " + LT_Par.ToString();
String s = ResultadoSQL.ToString();
return innovator.newError(s);

I do it using SQL because it is faster than creating an AML and going through it to add the values.

1.- There is something similar in AML to "select sum"

2.- How can I pass the value of "SQLResult" to a variable to be able to display it on the screen.

In c# I usually use:
return innovator.newError(s);

With this the execution stops and it shows me "s".

Too many thanks!!!!!!