Syntax for TIMESTAMPADD:

TIMESTAMPADD(interval, integer_expression, datetime_expression)

interval:= FRAC_SECOND | SECOND | MINUTE | HOUR | DAY | WEEK | MONTH | 
QUARTER | YEAR

Supported SQL_TSI_  prefix  (like SQL_TSI_SECOND)

Syntax for TIMESTAMPDIFF:

TIMESTAMPDIFF(interval, datetime_expression1, datetime_expression2)

interval:= FRAC_SECOND | SECOND | MINUTE | HOUR | DAY | WEEK | MONTH | 
QUARTER | YEAR

Supported SQL_TSI_  prefix  (like SQL_TSI_SECOND)