Node新手使用Node查询MySQL时遇ER_BAD_DB_ERROR错误求助

Hey there! Let's work through this MySQL error you're facing in your Node.js code—super common issue when starting out, so no worries.

First, let's break down the error #

The core problem here is the ER_BAD_DB_ERROR with the message Unknown database '201803028'. This means MySQL can't find a database named 201803028 on your local server. Also, there's a secondary issue in your SQL query that we'll fix too.

Step 1: Create the missing database #

1. Open your terminal and log into MySQL using your root credentials:

   mysql -u root -p
   

   When prompted, enter your password (123456).
2. Check what databases exist on your server:

   SHOW DATABASES;
   

   Look for 201803028 in the list—if it's not there, create it:

   CREATE DATABASE 201803028;
   

3. Verify it was created by running SHOW DATABASES; again, then exit MySQL with EXIT;.

Step 2: Fix the table name in your SQL query #

Your table name user-table uses a hyphen, which MySQL interprets as a subtraction operator instead of part of the table name. You need to wrap it in backticks to tell MySQL it's a single identifier. Also, you had a typo in your error log (console.log('err', e... should be err instead of e). Here's the corrected code snippet:

const mysql = require('mysql'); 
var db = mysql.createConnection({ 
  host:'localhost', 
  user:'root', 
  password:'123456', 
  database:'201803028'
}); 

// Add a connection check to catch early issues
db.connect((err) => {
  if (err) {
    console.error('Failed to connect to database:', err);
    return;
  }
  console.log('Successfully connected to MySQL!');
});

db.query('SELECT * FROM `user-table`;',(err,data)=>{ 
  if(err){ 
    console.log('Query error:', err); 
  } else {
    console.log('Query results:', data);
  }
  // Close the connection after the query (good practice)
  db.end();
});

Quick extra tip #

Always add error handling for the connection step—it helps you catch issues like wrong passwords or unavailable servers before even running your query.

内容的提问来源于stack exchange，提问作者Sylvia