NodeJS MySQL 从表中选择

简介：了解使用 node.js 从 MySQL 数据库中选择数据。我们将使用标准的 SELECT FROM SQL 查询。

句法：

SELECT [column] FROM [table_name]

例子：

1) SELECT * FROM customers
selecting all columns from customers table.

2) SELECT name, address FROM customers

SQL 用户表预览：

示例 1：从 users 表中选择所有列

index.js

const mysql = require("mysql");
  
let db_con  = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: '',
    database: 'gfg_db'
});
  
db_con.connect((err) => {
    if (err) {
      console.log("Database Connection Failed !!!", err);
      return;
    }
  
    console.log("We are connected to gfg_db database");
  
    // This query will be used to select columns
    let query = 'SELECT * FROM users';
  
    db_con.query(query, (err, rows) => {
        if(err) throw err;
  
        console.log(rows);
    });
});

输出：

示例 2：从用户表中选择名称列

索引.js

const mysql = require("mysql");
  
let db_con  = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: '',
    database: 'gfg_db'
});
  
db_con.connect((err) => {
    if (err) {
      console.log("Database Connection Failed !!!", err);
      return;
    }
  
    console.log("We are connected to gfg_db database");
  
    // notice the name column below
    let query = 'SELECT name FROM users';
  
    db_con.query(query, (err, rows) => {
        if(err) throw err;
  
        console.log(rows);
    });
});

输出：