Hi,
The 'round' mathematical function documentation doesn't specify its
rounding strategy. If this would be documented then users can rely on
its rounding behavior. For double precision the rounding probably
depends on your platform. For numeric the function seems to round to
nearest with ties going away from zero (sometimes referred to as "round
half up). 6.5 -> 7.0 and -6.5 -> -7.0.
https://www.postgresql.org/docs/current/functions-math.html
Kind regards, Rudolph