ER_PARSE_ERROR happens - mysql

Question

I want to do web scraping.I wrote codes
var connection = require('./mysqlConnection');
var c = new Crawler({
maxConnections : 10,
callback : function (error, result, $) {
if(error){
console.log(error);
}else{
const data = $(".test");
for(var i = 0; i < data.length; i ++){
const item = $(data[i]).text();
var query = 'INSERT INTO crawling (item) VALUES ("' + item + '")';
connection.query(query, function(err, rows) {
console.log(err);
});
}
}
}
});
c.queue('https://xxxxxxxxxx.com');
When I run this codes,const item could be gotten halfway through,but
{ Error: ER_PARSE_ERROR: 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 'June18th
")' at line 1
at Query.Sequence._packetToError (/Users/xxx/xxx/node_modules/mysql/lib/protocol/sequences/Sequence.js:52:14)
at Query.ErrorPacket (/Users/xxx/xxx/node_modules/mysql/lib/protocol/sequences/Query.js:77:18)
at Protocol._parsePacket (/Users/xxx/xxx/node_modules/mysql/lib/protocol/Protocol.js:279:23)
at Parser.write (/Users/xxx/xxx/node_modules/mysql/lib/protocol/Parser.js:76:12)
at Protocol.write (/Users/xxx/xxx/node_modules/mysql/lib/protocol/Protocol.js:39:16)
at Socket.<anonymous> (/Users/xxx/xxx/node_modules/mysql/lib/Connection.js:103:28)
at emitOne (events.js:116:13)
at Socket.emit (events.js:211:7)
at addChunk (_stream_readable.js:263:12)
at readableAddChunk (_stream_readable.js:250:11)
--------------------
at Protocol._enqueue (/Users/xxx/xxx/node_modules/mysql/lib/protocol/Protocol.js:145:48)
at Connection.query (/Users/xxx/xxx/node_modules/mysql/lib/Connection.js:208:25)
at Object.callback (/Users/xxx/xxx/app.js:135:24)
at Crawler._onInject (/Users/xxx/node_modules/node-webcrawler/lib/crawler.js:428:13)
at /Users/xxx/node_modules/node-webcrawler/lib/crawler.js:395:11
at Crawler._inject (/Users/xxx/node_modules/node-webcrawler/lib/crawler.js:154:9)
at Crawler._onContent (/Users/xxx/node_modules/node-webcrawler/lib/crawler.js:394:7)
at Request._callback (/Users/xxx/node_modules/node-webcrawler/lib/crawler.js:332:14)
at Request.self.callback (/Users/xxx/node_modules/node-webcrawler/node_modules/request/request.js:187:22)
at emitTwo (events.js:126:13)
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 \'June18th"\n \n \n ")\' at line 1',
sqlState: '42000',
index: 0,
sql: 'INSERT INTO crawling (title) VALUES (" \n I went to Paris at"June18th"because\n \n \n ")' }
I really cannot understand why such a error happens.I think \n causes this error, so I rewrote
const item = $(data[i]).text().replace("\n", '');
but same error happens.What is wrong in my codes?How should I fix this?

Answer 1

try changing: connection.query(query, function(err, rows) {
to connection.query([query], function(err, rows) {
it may need [] around it

Answer 2

You are adding the double quotes in your query to delimit the text in the insert statement, but you don't know if the incoming text will have double quotes too, hence the statement got malformed:
'INSERT INTO crawling (title) VALUES (" .. "June18th".. ")'
So, by "June18th" the sql went wrong.
Escaping the incoming text is a good practice, because you avoid sql injection and avoid these problems too; usually mysql(or any other database) modules have built-in escaping, using certain syntax in the query, or calling the escaping function directly. like this module https://github.com/mysqljs/mysql#escaping-query-values