What should I use in Mysqli bind_param() i or s

Question

I have numbers/digits and characters too in string. I want to insert it into database using mysqli bind_param('s', $string) . Is it okay or I have to use si both or what?

Answer 1

It is okay.

If you bind the parameter as int:

$stmt->bind_param('i', $bar);

Then the query will be about equivalent to:

INSERT INTO foo VALUES (42)

However, if you bind as string:

$stmt->bind_param('s', $bar);

The query will be about equivalent to:

INSERT INTO foo VALUES ('42')

Answer 2

A sequence of characters that contains both letters and digits is a string. You should use s for it.