What SQL query would I use to display the newest entry?
Details:
id is the primary field. I have other fields but that are not related to when they were added.
ORDER BY SomeColumn DESC
LIMIT 1
or
use the MAX() function
Since you didn't give any details about your table it is hard to answer
SELECT * from yourTable ORDER BY `id` DESC LIMIT 1;
Another (better) way would be to have a "date_added" column (date_added TIMESTAMP DEFAULT CURRENT_TIMESTAMP) so you could order by that column descending instead. Dates are more reliable than ID-assignment.
not sure if this is what your looking for but I use mysql_insert_id() after inserting a new row
The auto incremented ID columns are not always the latest records inserted, I've remember really painful experience with this behavior. Conditions where specific, it was mysql 4.1.x at the time and there was almost 1 million records, where 1 out of 3 deleted everiday, and others re inserted in the next 24hours. It made a huge mess when I realize ordering them via ID was not ordering them by age....
Since then, I use a specific column for doing age related sorts, and populating these fields with date = NOW() at each row insert.
Of course it will work to found the latest record as you want, doing an ORDER BY date DESC LIMIT 0,1on your query
SELECT Primary_Key_Field FROM table ORDER BY Primary_Key_Field DESC LIMIT 1
Replace Primary_Key_Field and table obviously :)
Related
I have one Sql Query to get all the informations from my table.
I created an list using an foreach.
And i want to order this list, by the last updated row.
Like this
$query - "SELECT * FROM table ORDER BY last_updated_row";
//call Query here
And when i updated a certain row, i want to put this row on the top of the list
I heard about time_stamp, can i use time_stamp for that?
how can i do that?
Thanks
Assuming your using MySQL your table needs to be like this
CREATE TABLE table (
last_updated_row TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);
That will give the row a create time stamp and update it on each update statement which effects the row
http://dev.mysql.com/doc/refman/5.0/en/timestamp-initialization.html
You can use just about any date/datetime/timestamp column in a table to sort by if needed. The only catch is you need to actually have it in the table.
Any of the above will allow sorts by ascending/descending order, but need to be maintained when inserting/updating a row.
Assuming you have the following structure:
table - someTable
id someVale updateTime
1 54634 ......
2 65138 ......
3 94141 ......
4 84351 ......
It doesn't matter what type of column updateTime is - whether it is a date, a datetime, a timestamp, a simple order by updateTime will work.
But you need to make sure that each insert/update you make to that row updates the column so that the sort will be true.
I would like to know how to update my database table with new data but having the latest data be at the top with the unique id starting at 1. Here's what I mean:
First insert query, for example, inserts 3 article topics:
id article
1 firstNews
2 secondNews
3 thirdNews
Then the next time I run a Cron job to check for new articles, for example two new articles appear, I want the two new articles to be in the beginning of the table, like this:
id article
1 NewArticle1
2 NewArticle2
3 firstNews
4 secondNews
5 thirdNews
Hope that made sense. This might be a bad way to do it, I guess I could have a column with insert date() and then get the data out OrderBy date but it has to be an easier way to do this. I think this would be the easiest to output the most recent data from the table...
If I do ORDER BY DESC, it would output NewArticle2 before NewArticle1, which would defeat the purpose...
id article
1 firstNews
2 secondNews
3 thirdNews
4 NewArticle1
5 NewArticle2
So by DESC, id 5 would be the first one output...I was really hoping there was a way around this...
You should never do this. Just insert at the end, and to get the latest articles, use a query:
SELECT * FROM articles ORDER BY id DESC;
In general: Don't fit the data to your query, fit the query to your data. The id is not a position or number, it uniquely identifies that row of data.
You could use a Date columns and sort on that. Or just sort by ID descending.
It's rarely a good idea to change a PK in place. Not least, you mah have child tables using that PK and maybe history tables too
Note that there is no implicit order to a SQL table: you always need an ORDER BY to guarantee the resultset order
You should add another column specifically for sorting, e.g. a date. and add an INDEX on it.
Then the query becomes:
SELECT *
FROM news
ORDER BY newsdate DESC
Latest news comes first
If there are two news items that could be posted at exactly the same time, you may wish to include a secondary sort:
ORDER BY newsdate DESC, id ASC
It shouldn't be your concern at all.
ID is not a number nor a position by any means. It's just an unique identifier.
Means every database row sticks to it's id forever. While you want to assign your "unique" id to the every newcoming news, which makes no sense.
So, just have usual autoincremented id and select it using ORDER BY id DESC to have latest entries first.
I have question, I want to insert new row to db (mysql) using php and I need to add it to first place in table, but it comes to last position.
I need to short it like this:
3
2
1
but it shorts like
1
2
3
Can you help me please?
Thanks a lot, Stepan
Assuming that you are using an incremental ID as the unique key, you can do:
order by id desc
if not, you can add a column to the DB called "created" which would be a datetime that you set to NOW() when you create the row. Then you would do:
order by created desc
SQL databases do not guarantee an order, unless you specify an ORDER BY clause.
If you have an identifier column, then you can do:
SELECT ...
FROM your_table
ORDER BY id DESC
I need help to write a MySQL query that would do the following for me:
It would select the last row from a certain column. Let's say the table name is 'mysite_codes' and the column name is 'code', there are many rows in this column, but I want the query to take the last added one and get my back one result in PHP (LIMIT 1 thing).
Would anyone please help me with this?
MySQL tables have no inherent sorting. If you want "the last added one" then you'll need an AUTO_INCREMENTing column like id.
Then you can write.
SELECT `code` FROM `mysite_codes` ORDER BY `id` DESC LIMIT 1
to get just the row with the highest id value.
Try this:
select code
from mysite_codes
order by add_date desc
limit 1
Assuming you have an auto-incremementing id column called something like "auto_id_column":
SELECT code FROM mysite_codes ORDER BY auto_id_column DESC LIMIT 0, 1;
I have a mysql database. How do I select the most recent 10 records? Im not storing timestamps. But the most the recent records are the ones at the bottom rite? Also. How so I get the next ten , the next ten and so on on clicking a button. Kinda like a bunch of forum posts. The recent ones show up first.
I believe you have an auto increment column as a primary key you can use this column and to order by desc
select * from table order by id desc limit 10
otherwise you have a very poor database design
If you have an AUTO_INCREMENT column you can order by that in descending order then limit by 10.
But I suggest you store timestamps and order by that instead so you know you're sorting your records according to date, and not some other value that coincides with date of insertion.
In addition to what #BoltClock mentioned, prequerying the maximum ID might help the engine with what other records are retrieved... ie: if you have a million records, and most recent 10, I don't know if it will still try to query out the million, order them, and THEN dump it.. I would try something like
select STRAIGHT_JOIN
YT.*
from
( select max( IDColumn ) as MaxOnFile
from YourTable ) PreQuery,
YourTable YT
where
YT.IDColumn >= PreQuery.MaxOnFile -10
order by
YT.IDColumn DESC
limit 10
However, if for some reason, records are allowed to be deleted, you may opt to subtract a little farther back than the -10... but at least this way, the system won't even TRY to process all the other records...