Exists methods don’t need table declaration in Dynamics Ax

static boolean SelectStatementInBooleanConditions()
{
//no declaration for table object has been made.
boolean test;
;

//testing a variable
test = (select firstonly salesTable).salesId ? true : false;

//if condition
if ((select firstonly salesTable).recid)
{
return true;
}

//switch statement
switch ((select firstonly salesTable).recid)
{
case 0:
return true;
case 1:
return false;
default:
return false;
}

//return statement
return ((select firstonly salesTable).recid);
}