MySQL parameterized queries

Beware of using string interpolation for SQL queries, since it won’t escape the input parameters correctly and will leave your application open to SQL injection vulnerabilities. The difference might seem trivial, but in reality it’s huge.

Incorrect (with security issues)

c.execute("SELECT * FROM foo WHERE bar = %s AND baz = %s" % (param1, param2))

Correct (with escaping)

c.execute("SELECT * FROM foo WHERE bar = %s AND baz = %s", (param1, param2))

It adds to the confusion that the modifiers used to bind parameters in a SQL statement varies between different DB API implementations and that the mysql client library uses printf style syntax instead of the more commonly accepted ‘?’ marker (used by eg. python-sqlite).

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