I have a table with 2 columns. Days is the days from Start Date to today.

How should Trigger be to automatically increase Days every day?

Start Date      Days  
19/07/17         19          
25/07/17         13
07/08/17         0

2 Answers 2


Triggers only work on the rows which are affected by the statement causing the trigger to execute.

When you want to update a whole table, use a normal statement, not triggers.

When you have data, that can be easily calculated, don't store this in a table. Either you calculate it in your SELECT statement or create a view.


CREATE VIEW view_with_day_difference_calculated AS
SELECT start_date, TIMESTAMPDIFF(day, start_date, NOW()) AS days
FROM your_table;

Then all you have to do is this in the future.

SELECT * FROM view_with_day_difference_calculated;

Another option would be to add the days calculation as a computed column.

  • Computed columns are not supported by SQLite AFAIK.
    – andrews
    Oct 18, 2017 at 8:57
  • Could you please describe this in more detail? Oct 18, 2017 at 9:58
  • My apologies i thought this was for sql server. Oct 19, 2017 at 6:45

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