IN Operator

OPERAND-A IN (OPERAND-B)

The IN operator checks whether OPERAND-A is found in OPERAND-B, where OPERAND-B is a comma-separated list of 1–1024 values (or expressions).
OPERAND-A and the members of OPERAND-B should be of the same type — either strings or integers.

For example, "genre IN ('Rock', 'Blues', 'R&B')" checks whether the value of a “genre” string attribute is identical to one of the genre strings in OPERAND-B (“Rock”, “Blues”, or “R&B”).