Syntax:
PERIOD_ADD(P,N)

Adds N months to period P (in the format YYMM or YYYYMM). Returns a
value in the format YYYYMM.

*Note*:

The period argument P is not a date value.

This function returns NULL if P or N is NULL.

URL: https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html

