New modifiers 'ceiling' and 'floor' control the algorithm used to
resolve ambiguous dates when shifting a date by an integer number
of months and/or years.
The 'utc' and 'localtime' modifiers are now no-ops if SQLite knows
that the time is already in UTC or in the localtime, respectively.
Add support for underscore ("_") characters between digits in
numeric literals.
The "VALUES-as-coroutine" optimization enables INSERT statements with
thousands of rows in the VALUES clause to parse and run in about half
the time and using about half as much memory.
Allow the use of an index for queries like "SELECT count(DISTINCT col) FROM ...",
even if the index records are not smaller than the table records.
Improved recognition of cases where the value of an SQL function is
constant because all its arguments are constant.
Allocate additional memory from the heap for the SQL parser stack if
that stack overflows, rather than reporting a "parser stack overflow" error.
JSON changes:
Allow ASCII control characters within JSON5 string literals.
Fix the -> and ->> operators so that when the right-hand side operand is a string
that looks like an integer it is still treated as a string, because that is what
PostgreSQL does.
Allow large hexadecimal literals to be used as the DEFAULT value to a table column.