Is the SQL NOW () function dynamic or static when updating large tables from a single query?

Question

If I write one SQL statement that updates a date field in a very large MySQL database table, is this SQL NOW () dynamic output function because it changes over time during its launch or does the field remain unchanged for all data and uses its start time?

IE will be:

UPDATE `table` SET `date` = NOW()

always leads to the same result (for example, 2016-10-17 15:33:10) in the entire field, regardless of whether 1 second or 1 hour to process?

If it is dynamic. I would like to help a little to create an expression where it is not.

Answer 1

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http://www.mysqltutorial.org/tryit/query/mysql-now/#3

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SYSDATE(), .