Node js - Mysql query is not executed as coded - mysql

Question

i created several sql statements in node.js and now i want to execute them on my db. However, the query string is not executed as coded.
This is my function to generate the query string.
function insertProducts(products) {
if (!connection) {
// Create MYSQL-Connection
console.log('BUILDING connection to DB');
connection = getConnection();
connection.connect();
}
let query = "";
for (let i = 0; i < products.length; i++) {
// Iterate trough the products array and create a sql query
query += "INSERT INTO `tShortDescription`(`ShortDescription`, `Language`) VALUES ('" + products[i].short_description + "', 'DE'); " +
"INSERT INTO `tDescription`(`Description`, `Language`) VALUES ('" + products[i].description + "', 'DE'); " +
"INSERT INTO `tManufacturer`(`Name`) VALUES ('" + products[i].manufactur + "'); " +
"INSERT INTO `tSupplier`(`Name`) VALUES ('" + products[i].supplier + "'); " +
"INSERT INTO `tProduct`(`Sku`, `Title`, `ShortDescriptionId`, `DescriptionId`, `WohlesalePrice`, `SellingPrice`, `Quantity`, " +
"`ManufacturerId`, `SupplierId`, `Ean`) VALUES ('" + products[i].sku + "', '" + products[i].name + "', " +
"(SELECT id FROM tShortDescription WHERE ShortDescription = '" + products[i].short_description + "' LIMIT 1), " +
"(SELECT id FROM tDescription WHERE Description LIKE '" + products[i].description + "' LIMIT 1), " +
products[i].wholesale_price + ", " + products[i].selling_price + ", " + products[i].quantity + ", " +
"(SELECT id FROM tManufacturer WHERE Name = '" + products[i].manufactur + "' LIMIT 1), " +
"(SELECT id FROM tSupplier WHERE Name = '" + products[i].supplier + "' LIMIT 1), " + products[i].ean + "); ";
for (let j = 0; j < products[i].categories.length; j++) {
// Ad all categories to query
query += "INSERT INTO `rtCategory`(`ProductId`, `CategoryId`) " +
"VALUES ((SELECT `Id` FROM `tProduct` WHERE sku = '" + products[i].sku + "' LIMIT 1), " +
"(SELECT `Id` FROM `tCategory` WHERE Id = " + products[i].categories[j].src + " LIMIT 1)); "
for (let c = 0; c < products[i].images.length; c++) {
// Ad all images to query
query += "INSERT INTO `tImage`(`Url`) VALUES ('" + products[i].images[c].src + "'); " +
"INSERT INTO `rtImage`(`ProductId`, `ImageId`) " +
"VALUES ((SELECT `Id` FROM `tProduct` WHERE sku = '" + products[i].sku + "' LIMIT 1), " +
"(SELECT `Id` FROM `tImage` WHERE url = '" + products[i].images[c].src + "' LIMIT 1)); "
}
}
}
query = query.replace(/[\n\r\t]/g,);
if (query != "") {
// Create new Product in DB
return new Promise((resolve, reject) => {
connection.query(query, function (error, results, fields) {
if (error) { console.log(error) };
console.log('INSERTING successful');
resolve(results);
});
});
} else {
console.log('There are no new products to insert in db');
}
}
If i console.log(query) (before the query is ecexuted on my db) and execute the string directly in php myadmin, everything works fine but if i execute the query in code like connection.query(query, function (error, results, fields)....., i got several errors.
Error msg in terminal:
code: 'ER_PARSE_ERROR',
errno: 1064,
sqlMessage: "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'INSERT INTO `tDescription`(`Description`, `Language`) VALUES ('<p><strong>Tantra' at line 1",
sqlState: '42000',
index: 0,
I also get the sql query returned in terminal because of the error, and if i execute this query directly in php myadmin i also get an error ->
SQL query: Documentation
INSERT INTO `rtImage`(`ProductId`, `ImageId`) VALUES ((SELECT `Id` FROM `tProduct` WHERE sku = 'H1500148' LM
IT 1), (SELECT `Id` FROM `tImage` WHERE url = 'https://cdnbigbuy.com/images/H1500148_409897.jpg' LIMIT 1))
MySQL said: Documentation
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LM
IT 1), (SELECT `Id` FROM `tImage` WHERE url = 'https://cdnbigbuy.com/images' at line 1
It looks as if the LIMIT is somehow divided ...use near 'LM IT 1)....
I hope you understand where the problem is and someone might have a tip.

Answer 1

Your query is processed as 'LIMIT' it's just a new line in the console where the error showed up.
You should not be using string concatenation (or even template literals) for SQL queries under any circumstances because 1. It very likely the source of your problem. 2. It's very dangerous as it allows SQL injection attacks.
Use parameters instead. Here's a example:
connection.query("SELECT * FROM bank_accounts WHERE dob = ? AND bank_account = ?",[
req.body.dob,
req.body.account_number
],function(error, results){});
To read more about SQL injections and placeholders read this article.

Answer 2

Thanks for the helpful tips.
The problem was that I didn't set multiple statements: true in my code. This var is by default false and should be true, otherwise it is not possible to execute several queries once at a request!