База данных: MySQL

expr IN (value,...)

Returns 1 (true) if expr is equal to any of the values in the IN()
list, else returns 0 (false).

Type conversion takes place according to the rules described in
https://dev.mysql.com/doc/refman/8.0/en/type-conversion.html, applied
to all the arguments. If no type conversion is needed for the values in
the IN() list, they are all non-JSON constants of the same type, and
expr can be compared to each of them as a value of the same type
(possibly after type conversion), an optimization takes place. The
values the list are sorted and the search for expr is done using a
binary search, which makes the IN() operation very quick.

URL: https://dev.mysql.com/doc/refman/8.0/en/comparison-operators.html


mysql> SELECT 2 IN (0,3,5,7);
-> 0
mysql> SELECT 'wefwf' IN ('wee','wefwf','weg');
-> 1