The UPDATE statement is given so that older fields can be updated to new value. If your older values are the same as your new ones, why would you need to update it in any case?

For eg. if your columns a to g are already set as 2 to 8; there would be no need to re-update it.

Alternatively, you can use:

INSERT INTO table (id,a,b,c,d,e,f,g)
VALUES (1,2,3,4,5,6,7,8) 
ON DUPLICATE KEY
    UPDATE a=a, b=b, c=c, d=d, e=e, f=f, g=g;

To get the id from LAST_INSERT_ID; you need to specify the backend app you're using for the same.

For LuaSQL, a conn:getlastautoid() fetches the value.

The fastest operation will be the one that has the most chances of succeeding immediately. You should find out what happens more often: inserting new rows or updating old ones. Code accordingly.

based on the reference doc you're using the wrong syntax. It expects the following formatting

INSERT INTO <table_name> (<column_name1>,<column_name2>) VALUES (<value1>,<value2>) 
ON DUPLICATE KEY UPDATE <column_name1> = <expression1>, <column_name2> = <expression2>;

Here's a link to the fiddle I used https://www.db-fiddle.com/f/3qCrm3bum7XEAtWbAX4gso/0

Unfortunately not.

You can get half-way there by not having to repeat the value:

INSERT INTO `tableName` (`a`,`b`,`c`) VALUES (1,2,3)
  ON DUPLICATE KEY UPDATE `a`=VALUES(`a`), `b`=VALUES(`b`), `c`=VALUES(`c`);

But you still have to list the columns.

You can only make alterations in the context of one conflicting row in the ON DUPLICATE KEY area. Further, this is, as far as I know, a property of the INSERT statement.

What you need is a simple ledger where you record the additions and subtractions from a balance, then tabulate those either manually or using triggers.

For instance, the simplest approach is:

INSERT INTO points_adjustments (boardId_from, boardId_to, points)
  VALUES (?, ?, ?)

This might be more easily represented as a pair of entries:

INSERT INTO points_adjustments (boardId, points)
  VALUES (?, ?)

You'd add one entry for +n points, and a matching one for -n. At any time you can get a balance using SUM(points). You could wrap this up in a VIEW to make retrieval easier, or if you want, denormalize the sums into a column of another table using a trigger.

A simple trigger would issue the following statement for each affected boardId:

INSERT INTO balances (boardId, points) VALUES (?, ?)
  ON DUPLICATE KEY SET points=points+VALUES(points)

This avoids key collisions in the first place and provides an auditable record of the transactions that occurred.

In any case, to do all of this automatically you'd probably have to use a trigger.

3rd party edit

From the docs INSERT ... ON DUPLICATE KEY UPDATE Statement

In general, you should try to avoid using an ON DUPLICATE KEY UPDATE clause on tables with multiple unique indexes.

Beginning with MySQL 8.0.19 you can use an alias for that row (see reference).

INSERT INTO beautiful (name, age)
    VALUES
    ('Helen', 24),
    ('Katrina', 21),
    ('Samia', 22),
    ('Hui Ling', 25),
    ('Yumie', 29)
    AS new
ON DUPLICATE KEY UPDATE
    age = new.age
    ...

For earlier versions use the keyword VALUES (see reference, deprecated with MySQL 8.0.20).

INSERT INTO beautiful (name, age)
    VALUES
    ('Helen', 24),
    ('Katrina', 21),
    ('Samia', 22),
    ('Hui Ling', 25),
    ('Yumie', 29)
ON DUPLICATE KEY UPDATE
    age = VALUES(age),
     ...