const mysql = require("mysql");
const config = {
    host:'127.0.0.1',
    user:'root',
    password:'',
    database : "test",
    connectionLimit : 10
}
const pool = mysql.createPool(config);
let strQuery = 'SELECT * FROM `test`';
//①getConnectionからqueryを実行
pool.getConnection(function(err,conn){
    if(err) throw err;
    conn.query(strQuery,function(error,results,fields){
        if(error) throw error;
        console.log(results);
        conn.release();
    });
});
//②直接queryを実行
pool.query(strQuery,function(error,results,fields){
    if(error) throw error;
    console.log(results);
});