SELECT WHERE IN in node-mysql

Question

Does anyone know how to use SELECT WHERE IN in node-mysql?

I've tried the code below, but I get the following error message:

'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 ''(`PHP`,`apache`)'' at line 1'

This is my code:

whereIn = '(';
for ( var i in tagArray ) {
    if ( i != tagArray.length - 1 ) {
        whereIn += "`" + tagArray[i] + "`,";    
    }else{
        whereIn += "`" + tagArray[i] + "`"; 
    }
}
whereIn += ')';

console.log(whereIn);

client.query(
    'SELECT tag_id FROM tag WHERE tag_name IN ?',
    [whereIn],
    function(err, result, fields) {
        client.destroy();

        if (err) {
            throw err;
        }

        console.log(result);

        res.redirect('/');
    }
);

Answer 1

You have to use IN (?) and NOT IN? .

Any string manipulation may result in a SQL INJECTION backdoor.

Answer 2

You simply need to pass the tagArray of values to node-mysql and it will handle the rest for you:

client.query(
    'SELECT tag_id FROM tag WHERE tag_name IN (?)',
    [tagArray],
    function(err, result, fields) {
        client.destroy();

        if (err) {
            throw err;
        }

        console.log(result);

        res.redirect('/');
    }
);

For more information, see the section in the manual for how different values are automatically escaped: https://github.com/mysqljs/mysql#escaping-query-values

Answer 3

You need to quote your strings, not use backticks.

whereIn = '(';
for ( var i in tagArray ) {
    if ( i != tagArray.length - 1 ) {
        whereIn += "'" + tagArray[i] + "',";    
    }else{
        whereIn += "'" + tagArray[i] + "'"; 
    }
 }
whereIn += ')';

Answer 4

For a more secure solution that avoids having to escape values, use? params like you would normally do, but create the param placeholders dynamically like this:

var inlist = '';
for(var i=0; i<ids.length; i++) {
  inlist += '?,';
}
inlist = inlist.substring(0,inlist.length-1);

var sql = 'SELECT a, b, c FROM mytable WHERE id in (' + inlist + ')';

conn.query( sql, ids, function(err, rows) {
  . . .
})

Answer 5

In case anyone is looking for answer to this in 2021.

 client.query(
      'SELECT tag_id FROM tag WHERE tag_name IN (?)', 
       [['val1', 'val2']],
       function(err, result, fields) {
    client.destroy();

    if (err) {
        throw err;
    }

    console.log(result);

    res.redirect('/');
}

);

Answer 6

A working solution:

client.query(
    'SELECT tag_id FROM tag WHERE tag_name IN ?',
    [tagArray],
    function(err, result, fields) {
        client.destroy();

        if (err) {
            throw err;
        }

        console.log(result);

        res.redirect('/');
    }
);

No need to manually wrap tagArray in quotes. It is escaped by the mysql module.