FORMAT_PICO_TIME(time_val)

Given a numeric Performance Schema latency or wait time in picoseconds,
converts it to human-readable format and returns a string consisting of
a value and a units indicator. The string contains the decimal time
rounded to 2 decimal places and a minimum of 3 significant digits.
Times under 1 nanosecond are represented as whole numbers and are not
rounded.

If time_val is NULL, this function returns NULL.

URL: https://dev.mysql.com/doc/refman/8.0/en/performance-schema-functions.html

