Search notes:

ORA-01898: too many precision specifiers in date format model

The following statement throws ORA-01898: too many precision specifiers in date format model on Oracle 23 or ORA-01898: too many precision specifiers on earlier versions:

select trunc(sysdate, 'yyyy-mm') from dual;

This one is ok:

select trunc(sysdate, 'mm') from dual;

ORA-01898: too many precision specifiers in date format model

See also