AWS Lambda 中的 NodeJs IF 语句使用 MySQL 数据库

Question

I am trying to pass an IF statement (IF data exists in table, [true] update data, [false] insert data) in NodeJS for either of the following queries:

var mysql = require('mysql');
var config = require('./config.json');
var pool  = mysql.createPool({
    host     : config.dbhost,
    user     : config.dbuser,
    password : config.dbpassword,
    database : config.dbname
  });

exports.handler = (event, context, callback) => {
  context.callbackWaitsForEmptyEventLoop = false;
  pool.getConnection(function(err, connection) {

      // IF STATEMENT
      var id = ... //select statement to the same table...??
      If (id = ?) {

          // If TRUE
          connection.query('UPDATE table SET email = "'johndoe@icloud.com'" WHERE id = 1;', function (error, results, fields) {
          // And done with the connection.
          connection.release();
          // Handle error after the release.
          if (error) callback(error) ;
          else callback(null, results);,
 
          // If FALSE
          connection.query('INSERT INTO table (id, name, email) VALUES (1, "'John Doe'", "'johndoe@gmail.com'");', event['i'], function (error, results, fields) {
          // And done with the connection.
          connection.release();
          // Handle error after the release.
          if (error) callback(error) ;
          else callback(null, results);

      }; 
    });
  });
};

I am new to NodeJS and I am still trying to figure out the IF STATEMENT with the codes I have above. I will keep you posted.

@CHRISWILLIAMS RESULTS DETAILS FOR HIS ANSWER

Basically, I have 2 APIs.

The first API runs initially, drop canvass_prices if exists. This one I don't have any issue. Here's the result of the first API:

Response:
[
  {
    "ID": 1,
    "Item": "Earth Science Deep Conditioning Masque For Hair - 2 Fl Oz",
    "Qty": 30,
    "Container": "Bottle",
    "Size": "750ml",
    "Reiciendis eos nostrum ut sequi.": 1680,
    "Sed quidem aspernatur quisquam ut.": 19920,
    "Aut dolorem repellendus iste nisi...": 79170
  }
]

Request ID:
"e2bbe38b-8121-4cb5-aa88-ac570b066759"

Function logs:
START RequestId: e2bbe38b-8121-4cb5-aa88-ac570b066759 Version: $LATEST
END RequestId: e2bbe38b-8121-4cb5-aa88-ac570b066759
REPORT RequestId: e2bbe38b-8121-4cb5-aa88-ac570b066759  Duration: 287.67 ms Billed Duration: 300 ms Memory Size: 128 MB Max Memory Used: 74 MB

And this is the 2nd API (see my 1st update here) which I am having trouble with. This API will update the canvass_prices created by 1st API.

However, the first time I clicked the result is this:

Response:
[
  {
    "ID": 1,
    "Item": "Earth Science Deep Conditioning Masque For Hair - 2 Fl Oz",
    "Qty": 30,
    "Container": "Bottle",
    "Size": "750ml",
    "Reiciendis eos nostrum ut sequi.": 1680,
    "Sed quidem aspernatur quisquam ut.": 19920,
    "Aut dolorem repellendus iste nisi...": 79170,
    "Voluptates laudantium voluptas nam.": null,
    "Ipsum voluptatem dolorum commodi.": null
  }
]

Request ID:
"4aed4c97-8ef6-485c-93b4-ca2eaf95703d"

Function logs:
START RequestId: 4aed4c97-8ef6-485c-93b4-ca2eaf95703d Version: $LATEST
END RequestId: 4aed4c97-8ef6-485c-93b4-ca2eaf95703d
REPORT RequestId: 4aed4c97-8ef6-485c-93b4-ca2eaf95703d  Duration: 393.79 ms Billed Duration: 400 ms Memory Size: 128 MB Max Memory Used: 75 MB

The the second and subsequent clicks solves my issue, it returns the correct results and will not further return duplicate "ID".

Response:
[
  {
    "ID": 1,
    "Item": "Earth Science Deep Conditioning Masque For Hair - 2 Fl Oz",
    "Qty": 30,
    "Container": "Bottle",
    "Size": "750ml",
    "Reiciendis eos nostrum ut sequi.": 1680,
    "Sed quidem aspernatur quisquam ut.": 19920,
    "Aut dolorem repellendus iste nisi...": 79170,
    "Voluptates laudantium voluptas nam.": null,
    "Ipsum voluptatem dolorum commodi.": null
  },
  {
    "ID": 9,
    "Item": "Laci Le Beau Maximum Strength Super Dieter's Tea Cinnamon Spice - 12 Tea Bags",
    "Qty": 10,
    "Container": "Bottle",
    "Size": "750ml",
    "Reiciendis eos nostrum ut sequi.": null,
    "Sed quidem aspernatur quisquam ut.": 30,
    "Aut dolorem repellendus iste nisi...": null,
    "Voluptates laudantium voluptas nam.": 1510,
    "Ipsum voluptatem dolorum commodi.": 17910
  }
]

Request ID:
"de40d4fa-06bb-433f-81d0-d667b2e2bca6"

Function logs:
START RequestId: de40d4fa-06bb-433f-81d0-d667b2e2bca6 Version: $LATEST
END RequestId: de40d4fa-06bb-433f-81d0-d667b2e2bca6
REPORT RequestId: de40d4fa-06bb-433f-81d0-d667b2e2bca6  Duration: 70.41 ms  Billed Duration: 100 ms Memory Size: 128 MB Max Memory Used: 75 MB

I wondering why it comes on the second click.

Answer 1

Assuming that this is specifically a NodeJS only answer then the problem is you are = rather than == . The single equals assigns Id to the value you're trying to compare to, whereas the double equals is the notation for is equal to. There's also === which presents as is identical to ( == does not care for type so 5=='5' would be true, whereas fail for identical to).

Below is the fixed code.

var mysql = require('mysql');
var config = require('./config.json');
var pool  = mysql.createPool({
    host     : config.dbhost,
    user     : config.dbuser,
    password : config.dbpassword,
    database : config.dbname
  });

exports.handler = (event, context, callback) => {
  context.callbackWaitsForEmptyEventLoop = false;
  pool.getConnection(function(err, connection) {

      // IF STATEMENT
      connection.query('SELECT id from table where id = ?', [event['id']], function (error, results, fields) {
          if (results.length > 0) {

              // If TRUE
              connection.query('UPDATE table SET email = "'johndoe@icloud.com'" WHERE id = 1;', function (error, results, fields) {
              // And done with the connection.
              connection.release();
              // Handle error after the release.
              if (error) callback(error) ;
              else callback(null, results);,
     
              // If FALSE
              connection.query('INSERT INTO table (id, name, email) VALUES (1, "'John Doe'", "'johndoe@gmail.com'");', event['i'], function (error, results, fields) {
              // And done with the connection.
              connection.release();
              // Handle error after the release.
              if (error) callback(error) ;
              else callback(null, results);

          }; 
        });
    });
  });

Answer 2

Or without an if statement and a race conditions:

exports.handler = (event, context, callback) => {
  context.callbackWaitsForEmptyEventLoop = false;
  pool.getConnection(function(err, connection) {
      connection.query('INSERT INTO table (id, name, email)
        VALUES (1, "John Doe", "johndoe@gmail.com")
        ON DUPLICATE KEY UPDATE table email = "johndoe@icloud.com";', function (error, results, fields) {
          // And done with the connection.
          connection.release();
          // Handle error after the release.
          if (error) callback(error) ;
          else callback(null, results);
      }; 
    });
  });

This assumes id is a primary or unique key in the table.