Select by varchar column with IN() part in condition and int value returns all rows

Question

Can someone explain me why with that query:

SELECT * FROM `tags` WHERE (tag IN (\'willa-lentza\', 2016))

it return me all rows from tags<

Answer 1

Interesting...i got this.

mysql> select 'a' in (0, 'b');
+-----------------+
| 'a' in (0, 'b') |
+-----------------+
|               1 |
+-----------------+
1 row in set, 1 warning (0.00 sec)

Warning (Code 1292): Truncated incorrect DOUBLE value: 'a'

EDIT: actually i think I can exaplain this one. (because 0 is in the in list, mysql thinks the rest og the in list and also the left hand argument 'a' should all be numbers. Casting 'a' will result in 0, so this will intenally be seen as 0 in (0, 0)

but I still can't explain the behavior of the OP