How to use variables in SQL statement in Python?

cursor.execute("INSERT INTO table VALUES (%s, %s, %s)", (var1, var2, var3))

Note that the parameters are passed as a tuple.

The database API does proper escaping and quoting of variables. Be careful not to use the string formatting operator (%), because

1. it does not do any escaping or quoting.
2. it is prone to Uncontrolled string format attacks e.g. SQL injection.

Different implementations of the Python DB-API are allowed to use different placeholders, so you'll need to find out which one you're using -- it could be (e.g. with MySQLdb):

cursor.execute("INSERT INTO table VALUES (%s, %s, %s)", (var1, var2, var3))

or (e.g. with sqlite3 from the Python standard library):

cursor.execute("INSERT INTO table VALUES (?, ?, ?)", (var1, var2, var3))

or others yet (after VALUES you could have (:1, :2, :3) , or "named styles" (:fee, :fie, :fo) or (%(fee)s, %(fie)s, %(fo)s) where you pass a dict instead of a map as the second argument to execute). Check the paramstyle string constant in the DB API module you're using, and look for paramstyle at http://www.python.org/dev/peps/pep-0249/ to see what all the parameter-passing styles are!

Many ways. DON'T use the most obvious one (%s with %) in real code, it's open to attacks.

Here copy-paste'd from pydoc of sqlite3:

# Never do this -- insecure!symbol = 'RHAT'c.execute("SELECT * FROM stocks WHERE symbol = '%s'" % symbol)# Do this insteadt = ('RHAT',)c.execute('SELECT * FROM stocks WHERE symbol=?', t)print c.fetchone()# Larger example that inserts many records at a timepurchases = [('2006-03-28', 'BUY', 'IBM', 1000, 45.00),             ('2006-04-05', 'BUY', 'MSFT', 1000, 72.00),             ('2006-04-06', 'SELL', 'IBM', 500, 53.00),            ]c.executemany('INSERT INTO stocks VALUES (?,?,?,?,?)', purchases)

More examples if you need:

# Multiple values single statement/executionc.execute('SELECT * FROM stocks WHERE symbol=? OR symbol=?', ('RHAT', 'MSO'))print c.fetchall()c.execute('SELECT * FROM stocks WHERE symbol IN (?, ?)', ('RHAT', 'MSO'))print c.fetchall()# This also works, though ones above are better as a habit as it's inline with syntax of executemany().. but your choice.c.execute('SELECT * FROM stocks WHERE symbol=? OR symbol=?', 'RHAT', 'MSO')print c.fetchall()# Insert a single itemc.execute('INSERT INTO stocks VALUES (?,?,?,?,?)', ('2006-03-28', 'BUY', 'IBM', 1000, 45.00))