Hi Derek,
Please use below script and it will give you output:
var query = xtk.queryDef.create(
<queryDef schema={vars.targetSchema} operation="select">
<select>
<node expr="Count(@id)" alias="var1"/>
</select>
</queryDef>
).ExecuteQuery();
for each( var row in query)
logInfo("Total products purchased: " + row.var1);
Thanks,
Jyoti