Is there a way in MySQL to get insert date/time for rows if there was no insert_date field. I have a database which I configured to store insert_date but can I populate the field before that change ( month ago ). Is that even possible?
Pull that insert date/time from log or something else?
Nope. If that date wasn't stored before, it's impossible to find out when a row was inserted. The best you can do is just pick a date, or maybe make a rough estimate if you have information to base that on (for instance, the create date of a customer might be related to the date of their first invoice)..
By the way, you can add timestamp columns and specify the clause DEFAULT CURRENT_TIMESTAMP to set a timestamp as soon as you insert the row. That way, you don't need a trigger to update the row.
You can even add a clause ON UPDATE CURRENT_TIMESTAMP so the column (or a different column) is updated automatically too.
See Timestamp initialization for more information about this subject.
This doesn't change the fact, though, that you cannot get those values for rows that already exist.
Related
I need to record the date each event happens. I have this table.
Click here to view the table
NULL spaces are available to save a new date.
The X represents the date that the event occurred.
The problem is I do not know how to update the date each event occurs
I need to know the best option if you use INSERT or UPDATE querys.
Thank you for your help
If you just want to update a column in a table with the current time:
UPDATE `yourtable` SET `yourcolumn` = NOW() WHERE `ID` = yourid
Assuming your columns are DATETIME() columns.
As an aside, it's best to have event-related information in another relationship table. This way you can link multiple events for each row in your main table. This provides a more accurate data-trail for accounting purposes (or in other words, you can see each and every update without overwriting anything).
If you are seeking to have a 'last_modified' column on your table to help you keep track of changes made on your records, you should do this:
ALTER TABLE my_table
ADD last_modified TIMESTAMP
DEFAULT CURRENT_TIMESTAMP
ON UPDATE CURRENT_TIMESTAMP;
Basically what it does is to add a 'last_modified' column, Set it to be a timestamp and make it to be updated with the current timestamp when there is an update on the record.
I have a database where people register on a website and their form data then gets inserted into their database. Along with all that information, I want to insert the time of their registration. For example I have an auto-incrementing ID column which I do nothing in my php script for, the sql database automatically increments that with every new entry. In the same way, can I have a time column that I don't have to do anything in the script for, rather the database will just get the current time and put that along with the other inserted information? I'm using phpMyAdmin and I tried adding a column named Time with the type as DATETIME and the default value as the CURRENT_TIMESTAMP but it woulnd't let me add that and said invalid default value for Time.
Change the column type to TIMESTAMP.
Use a timestamp field, which does exactly what you want.
use timestamp column type e.g.
`inserted` timestamp NOT NULL default CURRENT_TIMESTAMP
I need to know the time since a table in my MySQL database was edited. Is there any way to do this in PHP? The only way I can think of is to get the update time, and compare it to the current time (which will be a little bothersome).
SELECT TIMEDIFF(CURRENT_TIME, UPDATE_TIME)
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'my_table'
One solution would be to add a timestamp field, that is automatically updated whenever a row is changed.
Then you can find the last change time by selecting the last update value:
# Add a timestamp column:
ALTER TABLE [TABLENAME] add column `ts_update` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP;
# Get the last update value:
SELECT MAX(ts_update) from [TABLENAME];
It's a bit of a pain since SHOW TABLE STATUS doesn't seem to return a standard result set. Every way I tried to use it as a subquery failed. It seems like you'll need to figure it out programmatically.
SHOW TABLE STATUS
WHERE name = 'target_table';
And if you're concerned about the timezone just do a separate SELECT NOW() to get the time the mysql server has.
Note: This will only show you the time at which the table schema was updated. If you want to know when the last time a row was inserted/edited you'll have to add a timestamp column like Amirshk suggested.
I am creating my first (!) database, and I have run into an issue that I cannot seem to locate the answer for.
I have put an "added on" field in a table (among other things ofc), and since I'm the one adding it, I want to put the same date in the entire column. The idea is that if there is a new item added at a later date, it will have that date, but the data initially populated should all have the same date.
How? Please don't tell me one row at a time....
Just add the column to the table and then run an update query
update yourtable set nameofyournewfield = 'yourdate'
This will update all rows currently in the db, while the new rows will gettheir value (or have the default value you provided)
Another possibility in addition to #Nicola's answer is to use the DEFAULT argument in add column.
You can set default property of that column to any date and it will replicate that for all rows as long as you don't specify any value for that column while inserting and when you want to insert a different value just specify it in the insert statement.
I want to automatically add date in order_date field when a customer checkouts my online shop.
What is the best way to do it?
There are other fields like, delivery data and payment date in the same table.
Is it good idea to add a hidden field so that when a cutomer submit, the date will be added?
But I am not sure how to do it.
Can anyone suggests me the better way to do it please?
No, you don't need a hidden form field. You can do this directly in MySQL.
Assuming that your order_date field is a DATE. DATETIME or TIMESTAMP, then in your SQL that inserts the order record, simply put NOW() as the value for order_date:
INSERT INTO orders (x,y,z,order_date) VALUES ('x','y','z',NOW());
In the update statement that finalizes your order record, do something like this:
update order set ....., order_date = now() where ...
You don't want to rely on client-side date anyway. It could be off, and think of the timezones. You want a single source of dates in your system, and that should be either the database or the server-side code layer (PHP or what have you).
When a customer places an order you can use a TIMESTAMP column to track when the order was placed / the order was saved the database. Something like:
ALTER TABLE sales_order ADD COLUMN date_placed TIMESTAMP DEFAULT CURRENT_TIMESTAMP;
The DEFAULT CURRENT_TIMESTAMP will be filled with the current time when the row is created, but not on subsequent updates. See the docs for more:
http://dev.mysql.com/doc/refman/5.0/en/timestamp.html
With a DEFAULT CURRENT_TIMESTAMP
clause and no ON UPDATE clause, the
column has the current timestamp for
its default value but is not
automatically updated.