How to update/Insert random dates in SQL within a specified Date Range

Question

Please forgive me. I am an absolute newbie and I need help with this table in phpmyadmin

My Table has the following columns:

Primary_ID, Begin_Date, End_         


        

Answer 1

I'd start with something like this. A bunch of these can be combined, but I split it up so you can see what I'm doing.

To get random numbers, you can use rand(). Get one for the date, hour, minute, and second

$randomDate = rand(1,31);
$randomHour = rand(1,24);
$randomMinute = rand(0,59);
$randomSecond = rand(0,59);

You will want leading zeros (03 instead of 3) so you can use str_pad to add them, if required

$randomDate = str_pad($randomDate, 2, '0',STR_PAD_LEFT);
//The '2' is how many characters you want total
//The '0' is what will be added to the left if the value is short a character

Do the same with all your other random values. Just because I like neat queries, you should make up your final update strings next.

$newDate = '2008-09-'.$randomDate;
$newTime = $randomHour.':'.$randomMinute.':'.$randomSecond;

Now I don't know how you're determining which rows you want to update, so I will leave that up to you. For an example, I will show you a query if you wanted to do this with Primary_id 3:

$x = mysql_query("UPDATE yourTable SET Begin_Date=\"$newDate\", Timestamp=\"$newTime\" WHERE Primary_id = 3");

Answer 2

something like:

insert into myTable (begin_date) values date_add('2008-09-01', INTERVAL RAND()*30 DAY)

that should create a new row with a random begin_date

update myTable set Timestamp = date_add(begin_date, INTERVAL RAND()*1440 MINUTE)

then that one should set the timestamp to a random minute of that day.