How can I use upload.single() with if conditions ?

[mrcihantoker]

I am trying to code a "add product" page for my e-commerce website.I want system to get the input values and check the database for the product with the same name.If there isn't a product with the same name;I want system add the photo to 'Image' folder.How can I do it ?(enctype is set to multipart/form-data)

            app.post('/Add-Product-Check',function(req, res) {
                var product_name = req.body.add_product_product_name;
                var product_price = req.body.add_product_product_price;
                var product_category = req.body.add_product_categorie_section;


                var sql="SELECT COUNT(*) FROM products WHERE Product_name='productname'".replace("productname",product_name);

                server.query(sql,function(error,product_count_query,fields){

                    if(err){

                        throw err;
                    }

                    else{

                        var product_count=product_count_query[0]['COUNT(*)'];


                        if(product_count>0){

                            console.log("There is a product with this name.");
                        }

                        else{

                            upload.single('add_product_product_photo')(req,res,function(err){

                                if(err){

                                    throw err;
                                }

                                else{

                                    console.log("Photo uploaded!");
                                }
                            });
                        }
                    }
                });


                    
            });

[mrdulin]

Does your code not work? Is there any error? Show the debugging details.