How to truncate the seconds of a timestamp column?

i have a table with a date column in timestampz data type, example:

Table "power"

Some of the dates have an extra second at the end and i want to truncate it, so it looks like this

I tried UPDATE power SET date = DATE_TRUNC('second', date) FROM power; but it isn't working, hope someone can help me with this, thanks in advance.

Solution

Your code should work if you use 'minute', but you really don't want the FROM clause:

UPDATE power
    SET date = DATE_TRUNC('minute', date);

Here is a db<>fiddle.