As per the reference manual HQL accepts 'recognized SQL functions'.
When I try to use 'round' the situation appears to be as follows:

• MySQL supports round(number) and round(number, precision)
• Postgresql supports round(number) and round(number, precision) but in the latter case 'number' must not be a double. This leaves us with round(number)
• HSQLDB does not support round(number), only round(number,precision)

If an HQL query shall be DB independent 'round' appears to be unusable.
I found the following workaround:
The round function can be replaced using 'floor', e.g. for round(arg, 2) the following code can be used:

Any comments?

Hans