javascript - 如何使用express修复node.js中的ER_PARSE_ERROR

Question

我正在使用express在node.js中设置增删改查，我已经完成了创建和更新，但我仍然停留在删除功能

我试图分析 Handlebars 上的代码和/delete的路径，但仍然无法弄清楚为什么无法读取user_id

用户 ListView .hbs:

<form id="add-row-form" action="/delete" method="post">
<div class="modal fade" id="DeleteModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title" id="myModalLabel">Delete Product</h5>
                <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
            </div>
            <div class="modal-body">
                <strong>Do you want to delete this data ?</strong>
            </div>
            <div class="modal-footer">
                <input type="hidden" name="user_id" class="form-control user_id" required>
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                <button type="submit" class="btn btn-success">Delete</button>
            </div>
        </div>
    </div>
</div>

user_list_view.js 中的 jquery:

<script>
$(document).ready(function () {
    $('#mytable').on('click','.delete',function(){
        var user_id = $(this).data('user_id');
        $('#DeleteModal').modal('show');
        $('.user_id').val(user_id);
    });
})

process.js:

router.post('/delete', (req,res) => {
let sql = "DELETE FROM users WHERE user_id="+req.body.user_id
let query = db.query(sql, (err, results) => {
    if (err) throw err
    res.redirect('/user_list')
 })
})


module.exports = router

我预计结果会根据 user_id 删除所选用户，但收到错误消息:

code: 'ER_PARSE_ERROR',
errno: 1064,
sqlMessage: "You have an error in your SQL syntax; check the manual that 
corresponds to your MariaDB server version for the right syntax to use 
near ''at line 1",
sqlState: '42000',
index: 0,
sql: 'DELETE FROM users WHERE user_id='
}
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! latihan3@0.0.0 start: `node ./bin/www`
npm ERR! Exit status 1

Answer 1

在 mysql 的 .query 语法中，它需要 2 个参数，但第一个是你的查询，第二个是参数，而不是回调。除非你把它包装起来才能这样工作。

https://mariadb.com/kb/en/library/connector-nodejs-promise-api/

//不必执行此操作“从用户中删除 user_id="+req.body.user_id

let query = db.query('从用户中删除 user_id=,[req.body.user_id]).then(results => {
if (err) 抛出错误
res.redirect('/user_list')
})