I want to add x days to a datetime

[shaggycap]

I have a field in my DB called 'trial_start' which is a datetime with a default value of now().

There is another field in the DB called 'days' which is the no of days that the trial will run for.

I want another field, called 'trial_end' which is, you've guessed it, the 'trial_start' plus the number of days.

I am struggling as to what syntax to use, to calculate the 'trial_end' value. I assume I need to turn the days into seconds and add them onto the timestamp of the trial_start.

Can anyone help please as I'm struggling. Thanks

[fenway]

My first question is why store all three? You only need two of them, and the 3rd can always be calculated. Second, how much sense does it make to add a fixed number of days to a DATETIME column -- doesn't that mean the time of the trial_end value is meaningless?

Anyway, regardless, you can always use INTERVAL to set it (UNTESTED):

[code]UPDATE yourTable SET trial_end = trial_start + INTERVAL days DAY WHERE....[/code]

Hope that helps.

[obsidian]

... or, just do them all at once:

[!--sql--][div class=\'sqltop\']SQL[/div][div class=\'sqlmain\'][!--sql1--][span style=\'color:blue;font-weight:bold\']UPDATE[/span] tableName SET trial_end [color=orange]=[/color] DATE_ADD(trial_start, INTERVAL days DAY);
[!--sql2--][/div][!--sql3--]