diff --git a/index.js b/index.js
index 80db038..70414ac 100644
--- a/index.js
+++ b/index.js
@@ -129,34 +129,10 @@ server.post('/addmonth_v', bodyParser.json(), function (req, res) {
     var path = './route_sql/addmonth_vd.sql';
     
     var callback = function(arg){
-        sql = arg
-
-        for (var i in req.body.scenario) {
-            //console.log(i);
-            ///console.log(req.body[i]);
-            if (c > 1) {
-                w = w +
-                    `
-            AND `
-            }
-            if (Array.isArray(req.body.scenario[i])){
-                //if the scenario key has a value that is an array of items, push it into an `IN` statement
-                //iter = [stage1, stage2]   -->  SQL  -->  iter IN ('stag1', stage2')
-                w = w + i + " IN (";
-                for (var j in req.body.scenario[i]){
-                    if (d>1){
-                        w = w + ",";
-                    }
-                    w = w + "'" + req.body.scenario[i][j] + "'";
-                    d = d + 1;
-                }
-                w = w + ")"
-            } else {
-                w = w + i + " = '" + req.body.scenario[i] + "'";
-            }
-            args.push(req.body.scenario[i]);
-            c = c + 1;
-        };
+        sql = arg;
+        //buile where clause expression
+        ({ c, w, d } = build_where(req, c, w, d, args));
+        
         if (c == 1) {
             res.send("no body was sent");
             return;
@@ -373,4 +349,36 @@ server.post('/scale_vp', bodyParser.json(), function (req, res) {
     });
 })
 
+function build_where(req, c, w, d, args) {
+    for (var i in req.body.scenario) {
+        //console.log(i);
+        ///console.log(req.body[i]);
+        if (c > 1) {
+            w = w +
+                `
+            AND `;
+        }
+        if (Array.isArray(req.body.scenario[i])) {
+            //if the scenario key has a value that is an array of items, push it into an `IN` statement
+            //iter = [stage1, stage2]   -->  SQL  -->  iter IN ('stag1', stage2')
+            w = w + i + " IN (";
+            for (var j in req.body.scenario[i]) {
+                if (d > 1) {
+                    w = w + ",";
+                }
+                w = w + "'" + req.body.scenario[i][j] + "'";
+                d = d + 1;
+            }
+            w = w + ")";
+        }
+        else {
+            w = w + i + " = '" + req.body.scenario[i] + "'";
+        }
+        args.push(req.body.scenario[i]);
+        c = c + 1;
+    }
+    ;
+    return { c, w, d };
+}
+
 server.listen(3000, () => console.log('started'))
\ No newline at end of file