问题

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.

回答1:

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.

回答2:

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);

};

});

});

});

来源：https://stackoverflow.com/questions/63083370/nodejs-if-statement-in-aws-lambda-using-mysql-database