My below query returns a table with the corresponding values
union (traces), (customEvents)
| where timestamp <= now()
| summarize Users=dcount(user_AuthenticatedId) by Country=client_CountryOrRegion
| sort by Users desc
Results:
When pinning the query to the dashboard, I see different results:
The only difference that I can see is the time range set directly on the dashboard. I set this one to custom: 2016-07-06 to now to simulate the same value than in the query. I have checked and I only have logs from 2019 anyway.
Has anyone a clue?
Whenever I have seen this it is due to time slicing. You could add min and max timestamp values to the query in order to understand the exact ranges:
union (traces), (customEvents)
| where timestamp <= now()
| summarize Users=dcount(user_AuthenticatedId), FirstRecord=min(timestamp), LastRecord=max(timestamp) by Country=client_CountryOrRegion
| sort by Users desc
Related
I have a large table that gets anywhere from 1-3 new entries per minute. I need to be able to find records at specific times which I can do by using a SELECT statement but it's incredibly slow. Lets say the table looks like this:
Device | Date-Time | Data |
-----------------------------------
1 | 2020-01-01 08:00 | 325
2 | 2020-01-01 08:01 | 384
1 | 2020-01-01 08:01 | 175
3 | 2020-01-01 08:01 | 8435
7 | 2020-01-01 08:02 | 784
.
.
.
I'm trying to get data like this:
SELECT *
FROM table
WHERE Date-Time = '2020-01-01 08:00' AND Device = '1'
I also need to get data like this:
SELECT *
FROM table
WHERE Date-Time > '2020-01-01 08:00' Date-Time < '2020-01-10 08:00' AND Device = '1'
But I don't know what the Date-Time will be until requested. In this case, I will have to search the entire table for these times. Can I index the start of the day so I know where dates are?
Is there a way to index this table in order to dramatically decrease the queries? Or is there a better way to achieve this?
I have tried indexing the Date-Time column but I did not decrease the query time at all.
For this query:
SELECT *
FROM mytable
WHERE date_time = '2020-01-01 08:00' AND device = 1
You want an index on mytable(date_time, device). This matches the columns that come into play in the WHERE clause, so the database should be able to lookup the matching rows efficiently.
Note that I removed the single quotes around the literal value given to device: if this is an integer, as it looks like, then it should be treated as such.
The ordering of the column in the index matters; generally, you want the most restrictive column first - from the description of your question, this would probably be date_time, hence the above suggestion. You might want to try the other way around as well (so: mytable(device, date_time)).
Another thing to keep in mind from performance perspective: you should probably enumerate the columns you want in the SELECT clause; if you just want a few additional columns, then it can be useful to add them to the index as well; this gives you a covering index, that the database can use to execute the whole query without even looking back at the data.
Say:
SELECT date_time, device, col1, col2
FROM mytable
WHERE date_time = '2020-01-01 08:00' AND device = 1
Then consider:
mytable(date_time, device, col1, col2)
Or:
mytable(device, date_time, col1, col2)
You can use TimeInMilliseconds as new column and populate it with milliseconds from the year 1970 and create Index on this column. TimeInMilliseconds will always be unique number and it will help the index to search queries faster.
I'm looking into Azure Monitor queries for the first time, and can't understand why adding this line:
| where timestamp <= ago(1days)
makes the query results "de-aggregated."
Screenshots of the 2 separate queries/results:
Desired Output
Undesired Output
The operator you should be using is timestamp >= ago(1d), which should pick the rows which have timestamp for last 24Hrs.
Below is the sample
requests
| where timestamp >= ago(1d)
| summarize C = count() by itemType
Output from Explorer with timestamp with in the query
requests
| summarize C = count() by itemType
Output from Explorer with timestamp from Time Range
Documentation reference for using ago()
Hope this helps !
SQL Server 2008, rendered in html via aspx webpage.
What I want to achieve, is to get an average per day figure that makes allowance for missing days. To do this I need to count the number of active days in a table.
Example:
Date | Amount
---------------------
2014-08-16 | 234.56
2014-08-16 | 258.30
2014-08-18 | 25.84
2014-08-19 | 259.21
The sum of the lot (777.961) divided by the number of active days (3) would = 259.30
So it needs to go "count number of different dates in the returned range"
Is there a tidy way to do this?
If you just want that one row of output then this should work:
select sum(amount) / count(distinct date) as your_average
from your_table
Fiddle:
http://sqlfiddle.com/#!2/7ffd1/1/0
I don't know this will be help to you, how about using Group By, Avg, count function.
SELECT Date, AVG(Amount) AS 'AmountAverage', COUNT(*) AS 'NumberOfActiveDays'
FROM YourTable WITH(NOLOCK)
GROUP BY Date
About AVG function, see here: Link
I would like to retrieve the records in certain dates after d/mm/yyyy, or after d/mm/yyyy and before d/mm/yyyy, how can I do it ?
SELECT date
FROM table
WHERE date > 1/09/2008;
and
SELECT date
FROM table
WHERE date > 1/09/2008;
AND date < 1/09/2010
It doesn't work.
Be careful, you're unwittingly asking "where the date is greater than one divided by nine, divided by two thousand and eight".
Put # signs around the date, like this #1/09/2008#
The semicolon character is used to terminate the SQL statement.
You can either use # signs around a date value or use Access's (ACE, Jet, whatever) cast to DATETIME function CDATE(). As its name suggests, DATETIME always includes a time element so your literal values should reflect this fact. The ISO date format is understood perfectly by the SQL engine.
Best not to use BETWEEN for DATETIME in Access: it's modelled using a floating point type and anyhow time is a continuum ;)
DATE and TABLE are reserved words in the SQL Standards, ODBC and Jet 4.0 (and probably beyond) so are best avoided for a data element names:
Your predicates suggest open-open representation of periods (where neither its start date or the end date is included in the period), which is arguably the least popular choice. It makes me wonder if you meant to use closed-open representation (where neither its start date is included but the period ends immediately prior to the end date):
SELECT my_date
FROM MyTable
WHERE my_date >= #2008-09-01 00:00:00#
AND my_date < #2010-09-01 00:00:00#;
Alternatively:
SELECT my_date
FROM MyTable
WHERE my_date >= CDate('2008-09-01 00:00:00')
AND my_date < CDate('2010-09-01 00:00:00');
select Qty, vajan, Rate,Amt,nhamali,ncommission,ntolai from SalesDtl,SalesMSt where SalesDtl.PurEntryNo=1 and SalesMST.SaleDate= (22/03/2014) and SalesMST.SaleNo= SalesDtl.SaleNo;
That should work.
hey guys i think what you are looking for is this one using select command.
With this you can specify a RANGE GREATER THAN(>) OR LESSER THAN(<) IN MySQL WITH THIS:::::
select* from <**TABLE NAME**> where year(**COLUMN NAME**) > **DATE** OR YEAR(COLUMN NAME )< **DATE**;
FOR EXAMPLE:
select name, BIRTH from pet1 where year(birth)> 1996 OR YEAR(BIRTH)< 1989;
+----------+------------+
| name | BIRTH |
+----------+------------+
| bowser | 1979-09-11 |
| chirpy | 1998-09-11 |
| whistler | 1999-09-09 |
+----------+------------+
FOR SIMPLE RANGE LIKE USE ONLY GREATER THAN / LESSER THAN
mysql>
select COLUMN NAME from <TABLE NAME> where year(COLUMN NAME)> 1996;
FOR EXAMPLE
mysql>
select name from pet1 where year(birth)> 1996 OR YEAR(BIRTH)< 1989;
+----------+
| name |
+----------+
| bowser |
| chirpy |
| whistler |
+----------+
3 rows in set (0.00 sec)
What is the most efficient way to get a list of all of the unique Mondays from a date field?
When I'm not all that concerned about efficiency, I have done something like:
DATE-weekday(DATE) + 1. But now I need to compute this on a large dataset and I don't want my user wishing for a Rubik's cube because it is taking so long. :)
Yes, the field is indexed.
EDIT:
What I need is a list of all of the weeks that contain records. I am creating a payroll report where the user will select the week to filter the report.
Here is what I came up with:
SELECT DISTINCT ((DATE(`timStart`)-DAYOFWEEK(`timStart`))+2)
FROM `time`
ORDER BY 1 DESC
Anyone have any improvement to suggest?
"unique mondays from a date field" should be as simple as:
SELECT DISTINCT(`date`) FROM `table` WHERE WEEKDAY(`date`)=0
"weeks in which we have date values" should be as simple as:
SELECT DISTINCT(WEEK(`date`)) FROM `table` WHERE YEAR(`date`)=2010;
SELECT WEEK(now()),YEAR(now());
+-------------+-------------+
| WEEK(now()) | YEAR(now()) |
+-------------+-------------+
| 31 | 2010 |
+-------------+-------------+
which will benefit you as well in your other payroll queries, using
WHERE WEEK(`date`)=31
Put your trust in mysql to handle things from there.