I have a table containing events which happen in my application like people logging in and people changing settings.
They have a date/time against the event in the following format:
2010-01-29 10:27:29
Is it possible to use SQL to select the events that have only happened in the last 5 mins?
So if the date/time was 2010-01-29 10:27:29 it would only select the events that happened between 10:27:29 and 10:22:29?
Cheers
Eef
SELECT foo FROM bar WHERE event_time > DATE_SUB(NOW(), INTERVAL 5 MINUTES)
(Not sure if it's minutes or minute)
WHERE my_timestamp < DATE_SUB(now(), INTERVAL 5 MINUTE)
You should provide table and column names to make it easy for us to answer your question.
You can write SQL as
SELECT *
FROM Table
WHERE DateTimeColumnName <= '2010/01/29 10:27:29'
AND DateTimeColumnName >= '2010/01/29 10:22:29'
or you can use BETWEEN
SELECT *
FROM Table
WHERE DateTimeColumnName BETWEEN '2010/01/29 10:22:29' AND '2010/01/29 10:27:29'
Now see if there are datetime functions in MySQL to do a Date Math so just pass a single date stamp, and do the math to subtract 5 min from it and use it as the second parameter in the between clause.
Related
I'm coming to you guys with with two small oddities I can't seem to understand with postgres:
(1)
SELECT "LASTREQUESTED",
(DATE_TRUNC('seconds', CURRENT_TIMESTAMP - "LASTREQUESTED")
- INTERVAL '8 hours') AS "TIME"
FROM "USER" AS u
JOIN "REQUESTLOG" AS r ON u."ID" = r."ID"
ORDER BY "TIME"
I'm calculating when users can make their next request [once every 8 hours], but if you look at entry 16 I get "1 day -06:20:47" instead of "18:00:00" ish, unlike every other line. [The table LASTREQUESTED is a simple timestamp, nothing different here from the other entries for line 16], why is that?
(2)
On the same request, if I try to add a condition on the "TIME" column, the compiler says it doesn't exist although using it to order by is ok. I don't get why.
SELECT (DATE_TRUNC('seconds', CURRENT_TIMESTAMP - "LASTREQUESTED")
- INTERVAL '8 hours') AS "TIME"
FROM "USER" AS u
JOIN "REQUESTLOG" AS r ON u."ID" = r."ID"
WHERE "TIME" > 0
ORDER BY "TIME";
Question #1: negative hours but positive days?
According to the PostgreSQL documentation, this is a situation where PostgreSQL differs from the SQL standard:
According to the SQL standard all fields of an interval value must have the same sign…. PostgreSQL allows the fields to have different signs….
Internally interval values are stored as months, days, and seconds. This is done because the number of days in a month varies, and a day can have 23 or 25 hours if a daylight savings time adjustment is involved. The months and days fields are integers while the seconds field can store fractions. …
You can see a more extreme example of this with the following query:
=# select interval '1 day' - interval '300 hours';
?column?
------------------
1 day -300:00:00
(1 row)
So this is not a single interval in seconds expressed in a strange way; instead, it's an interval of 0 months, +1 day, and -1,080,000.0 seconds. If you are certain that there's no daylight savings time issues with the timestamps that you got these intervals from, you can use justify_hours to convert days into 24-hour periods and get an interval that makes more sense:
=# select justify_hours(interval '1 day' - interval '300 hours');
justify_hours
--------------------
-11 days -12:00:00
Question #2: SELECT columns can't be used in WHERE?
This is standard PostgreSQL behavior. See this duplicate question. Solutions presented there include:
Repeat the expression twice, once in the SELECT list, and again in the WHERE clause. (I've done this more times than I want to remember…)
SELECT (my - big * expression) AS x
FROM stuff
WHERE (my - big * expression) > 5
ORDER BY x
Create a subquery without that WHERE filter, and put the WHERE conditions in the outer query
SELECT *
FROM (SELECT (my - big * expression) AS x
FROM stuff) AS subquery
WHERE x > 5
ORDER BY x
Use a WITH statement to achieve something similar to the subquery trick.
I don't now exactly why it's calculating as-is (maybe because you subtract an Interval from another Interval) but when you change the calculation to Timestamp minus Timestamp it works as expected:
DATE_TRUNC('seconds', CURRENT_TIMESTAMP - (LASTREQUESTED + INTERVAL '8 hours'))
See Fiddle
Regarding #2: Based on Standard SQL the columns in the Select-list are calculated after FROM/WHERE/GROUP BY/HAVING, but before ORDER, that's why you can't use an alias in WHERE. There are some good articles on that topic written by Itzik Ben-Gan (based on MS SQL Server, but similar for PostgreSQL).
I am trying to do a query that chart date is the system time the data was charted is more than 8 hrs after the perform date time.
I am using the following query:
select * from pat_results where app_type like 'L' and (chart_dt_utc > perform_dt_utc +8)
The date and time format for both columns are 2012-12-29 11:44:00
Is the +8 correct?
No. In databases that allow you to add a number to a date, the number is measured in days.
The value you want to add is 8/24.0 -- include the decimal place, because some databases calculate 8/24 as integers and give you 0.
No, + 8 adds 8 days. You want:
select * from pat_results where app_type like 'L' and datediff(hour, chart_dt_utc, perform_dt_utc) > 8
Edit: Oh. For some reason I thought you were using SQL server. Well, suffice it to say, use whatever equivalent exists in your RDBMS.
Edit 2: In Oracle you can do this:
select * from pat_results where app_type like 'L'
and (chart_dt_utc > perform_dt_utc + (8 / 24))
I am trying to write a query to run on Oracle database. The table ActionTable contains actionStartTime and actionEndTime columns. I need to find out which action took longer than 1 hour to complete.
actionStartTime and actionEndTime are of timestamp type
I have a query which gives me the time taken for each action:
select (actionEndTime - actionStartTime) actionDuration from ActionTable
What would be my where clause that would return only actions that took longer than 1 hour to finish?
Subtracting two timestamps returns an interval. So you'd want something like
SELECT (actionEndTime - actionStartTime) actionDuration
FROM ActionTable
WHERE actionEndTime - actionStartTime > interval '1' hour
HI all,
i have one sql table and field for that table is
id
name
expireydate
Now i want only those record which one is expired within 45 days or 30 days.
how can i do with sql query .?
I have not much more exp with sql .
Thanks in advance,
If you are using mysql then try DATEDIFF.
for 45 days
select * from `table` where DATEDIFF(now(),expireydate)<=45;
for 30 days
select * from `table` where DATEDIFF(now(),expireydate)<=30;
In oracle - will do the trick instead of datediff and SYSDATE instead of now().[not sure]
In sql server DateDiff is quite different you have to provide unit in which difference to be taken out from 2 dates.
DATEDIFF(datepart,startdate,enddate)
to get current date try one of this: CURRENT_TIMESTAMP or GETDATE() or {fn NOW()}
You can use a simple SELECT * FROM yourtable WHERE expireydate < "some formula calculating today+30 or 45 days".
Simple comparison will work there, the tricky part is to write this last bit concerning the date you want to compare to. It'll depend of your environment and how you stored the "expireydate" in the database.
Try Below:-
SELECT * FROM MYTABLE WHERE (expireydate in days) < ((CURRENTDATE in days)+ 45)
Do not execute directly! Depending of your database, way of obtaining a date in days will be different. Go look at your database manual or please precise what is your database.
What's the best way to select only those rows from the table that have been created in last 7 days?
There are dozens of time and date functions in MySQL and I'm a little bit confused about what's the easiest way to do this.
For the sake of this question, assume that you have a table called "my_table" and it contains a row "created_at" which is a DATETIME.
SELECT * FROM my_table WHERE ...
What would you fill in the WHERE clause?
WHERE DATEDIFF(NOW(), created_at) <= 7;
I like it because it reads: "Where the Difference in Date between Now and when it was created is at most 7 (days)." in my own head
...WHERE created_at >= Date_Add(now(), INTERVAL -7 DAY)
This is my preferred way because it's so...clear. But ADDDATE is fine too (and you can use the INTERVAL form with that for clarity as well; its default is days so you see people leaving it off). You don't want to do a calculation on created_at and compare it to now() because that requires the computation on created_at on each row (assuming MySQL doesn't optimise it out), whereas modifying now() and comparing to an unmodified created_at means MySQL does that bit once and uses the result when comparing against rows, not to mention indexes.
...... WHERE created_at >= DATE_SUB(CURRENT_DATE, INTERVAL 7 DAY)
hopefully that will help
WHERE ADDDATE(datefield, 7) > NOW();
SELECT * FROM my_table
WHERE DATE(created_at) >= SUBDATE(DATE(NOW()), 7)
SELECT * FROM my_table WHERE my_table.datefield > sysdate - 7