I need insert or delete in mysql data

Hey, developers!
Now I learning REACT Back-End with using EXRESS, Node.js. I need insert or delete in mysql data . Front-end works partially, but don’t work back-end , INSERT and DELETE in customers.js. SELECT from MYSQL I received and I see in browser. How insert and delete data in MYSQL using REACT,EXPRESS,NODE.js?

customers.js

const express=require("express");
const app = express();
const database = require('../config/database');
const moment = require('moment');
const bodyParser = require("body-parser");
const urlencodedParser = bodyParser.urlencoded({extended: false});
app.get('/customers',(req,res)=>{
let sql='SELECT*FROM customers';
database.query(sql,(err,result)=>{
if(err){
res.status(400).send(err);
return; }
if(result.length)res.json(result);
else res.json({});
});});
app.post('/customers', function(req, res) {
var customers = req.body;
var query = con.query('INSERT INTO customers SET ?', customer, function(err, result) {
});
res.end('Success');
});
app.post("/delete/:id", function(req, res){
const id = req.params.id;
var query = con.query("DELETE FROM users WHERE id=?", [id], function(err, result) {
});
});
module.exports=app;

App.js

import React from 'react';
import {useEffect, useState} from "react";
function App() {
const [error, setError] = useState(null);
const [isLoaded, setIsLoaded] = useState(false);
const [items, setItems] = useState([]);
const [name, setName] = useState("");
const [address, setAddress] = useState("");
function deletBox(index){
const copy=Object.assign([],items);
copy.splice(index,1);
setItems(copy);
}
useEffect(() => {
fetch("http://localhost:5000/customers")
.then(res => res.json())
.then(
(result) => {
setIsLoaded(true);
setItems(result);
},
(error) => {
setIsLoaded(true);
setError(error);
} ) }, [])
if (error) {
return <div>Ошибка: {error.message}</div>;
} else if (!isLoaded) {
return <div>Loade...</div>;
} else {
return (
<div><center>
<input type="text" value={name} placeholder="name"
onChange={(e)=>{setName(e.target.value);}} />
<input type="text" value={address} placeholder="address"
onChange={(e)=>{setAddress(e.target.value);}} />
<input type="button" value="ADD_BUTTON"
onClick={(e)=>
{setItems([...items,{id:items.length+1,name:name,address:address}]);
console.log(name);
}} />
{items.map(item => (
<h2 key={item.id}>
{item.name} {item.address}
<button type="button" onClick={deletBox} >delete</button>
</h2>
))}
</center></div>
);
}
}
export default App;