L.rp L.rp - 4 months ago 21
MySQL Question

node-mysql multiple statement in one

I'm using

nodejs 10.26
+
express 3.5
+
node-mysql 2.1.1
+
MySQL-Server Version: 5.6.16
.

I got 4 DELETE's and want only 1 Database Request, so i connected the DELETE commands with a ";"... but it fails always.

var sql_string = "DELETE FROM user_tables WHERE name = 'Testbase';";
sql_string += "DELETE FROM user_tables_structure WHERE parent_table_name = 'Testbase';";
sql_string += "DELETE FROM user_tables_rules WHERE parent_table_name = 'Testbase';";
sql_string += "DELETE FROM user_tables_columns WHERE parent_table_name = 'Testbase';";

connection.query(sql_string, function(err, rows, fields) {
if (err) throw err;
res.send('true');
});


It throws this error:

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 'DELETE FROM user_tables_structure WHERE parent_table_name = 'Testbase';DELETE FR' at line 1


But if i paste this SQL in PhpMyAdmin it is always successful...

If i write it in single query's its succeed, too.

connection.query("DELETE FROM user_tables WHERE name = 'Testbase'", function(err, rows, fields) {
if (err) throw err;

connection.query("DELETE FROM user_tables_structure WHERE parent_table_name = 'Testbase'", function(err, rows, fields) {
if (err) throw err;


connection.query("DELETE FROM user_tables_rules WHERE parent_table_name = 'Testbase'", function(err, rows, fields) {
if (err) throw err;

connection.query("DELETE FROM user_tables_columns WHERE parent_table_name = 'Testbase'", function(err, rows, fields) {
if (err) throw err;

res.send('true');
});
});
});
});


Thanks for help!

Answer

I guess you are using node-mysql. The docs says:

Support for multiple statements is disabled for security reasons (it allows for SQL injection attacks if values are not properly escaped).

Multiple statement queries

To use this feature you have to enable it for your connection:

var connection = mysql.createConnection({multipleStatements: true});

Once enabled, you can execute multiple statement queries like any other query:

connection.query('SELECT ?; SELECT ?', [1, 2], function(err, results) {
  if (err) throw err;

  // `results` is an array with one element for every statement in the query:
  console.log(results[0]); // [{1: 1}]
  console.log(results[1]); // [{2: 2}]
});

So if you've enabled the multipleStatements then your first code should work.

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