I have a very simple MYSQL table, which tracks the weights of some animals:
id
name
weight
date
1
Brillo
400
2022-12-01
2
Barli
200
2022-12-01
3
Bueno
350
2022-12-01
4
Brillo
410
2022-12-10
5
Barli
197
2022-12-10
6
Bueno
362
2022-12-10
So in the example above, I weight my 3 animals on the 1st, then again on the 10th.
I would like to visualize this data in Grafana with a timeseries panel. I get the exact data I want, if I query the database once per pet:
SELECT name, weight as 'Brillo', date FROM animal.weights WHERE name='Brillo'
SELECT name, weight as 'Bueno', date FROM animal.weights WHERE name='Bueno'
SELECT name, weight as 'Barli', date FROM animal.weights WHERE name='Barli'
This gives me the following panel:
Whilst this works, doing 1 query per animal feels like the wrong approach. I will eventually have 20+ on here, so doing 20 queries to the database every time feels incorrect.
My question is this; Is there a way I can get the same results from my table into a Grafana timeseries panel in a single query?
SELECT name, weight, date FROM animals.weights
You need aggregation per name and date + also time filter (otherwise you will have a problem with a lot of records in the DB).
This is a good start:
SELECT
$__timeGroup(date, '1d', NULL),
name AS "metric",
AVG(weight) AS "value"
FROM animals.weights
WHERE
$__time(date)
ORDER BY 1
See Grafana MySQL doc for used macros.
Related
I have been struggling with the following for some time.
The server I am using has MySQL ver 5.7 installed.
The issue:
I wish to take recorded tank level readings from one table, find the difference between the last two records for a particular tank, and multiply this by a factor to get a quantity used.
The extracted quantity, if it is +ve, else 0 , then to be inserted into another table for further use.
The Quant value extracted may be +ve or -ve as tanks fill and empty. I only require the used quantity -ie falling level.
The two following tables are used:
Table 'tf_rdgs' sample;
value 1 is content height.
id
location
value1
reading_time
1
18
1500
2
18
1340
3
9
1600
4
18
1200
5
9
1400
6
18
1765
yyyy
7
18
1642
xxxx
Table 'flow' example
id
location
Quant
reading_time
1
18
5634
dd-mm: HH-mm
2
18
0
dd-mm: HH-mm
3
18
123
current time
I do not require to go back over history and am only interested in the latest level readings as a new level reading is inserted.
I can get the following to work with a table of only one location.
INSERT INTO flow (location, Quant)
SELECT t1.location, (t2.value1 - t1.value1) AS Quant
FROM tf_rdgs t1 cross join tf_rdgs t2 on t1.reading_time > t2.reading_time
ORDER BY t2.reading_time DESC limit 1
It is not particularly efficient but works and gives the following return from the above table.
location
Quant
18
123
for a table with mixed locations including a WHERE t1.location = ... statement does not work.
The problems i am struggling with are
How to nest the initial sorting by location for the subsequent inquiry of difference between the last two tank level readings.
A singular location search is ok rather than all tanks.
A Conditional INSERT to insert the 'Quant' value only if it is +ve or else insert a 0 if it is -ve (ie filling)
I have tried many permutations on these without success.
Once the above has been achieved it needs to run on a conditional trigger - based upon location of inserted data - in the tf_rdgs table activated upon each new reading inserted from the sensors on a particular tank.
I can achieve the above with the exception of the conditional insert if each tank had a dedicated table but unfortunately I cant go there due existing data structure and usage.
Any direction or assitance on parts or whole of this much appreciated.
I have two tables as below:
goods_in:
in_id|pid|in_num|in_date
1 1001 10 2020-06-28
2 1002 20 2020-06-28
3 1001 20 2020-05-25
......
stock:
stock_id|pid|num|price
1 1001 10 5
2 1002 15 6
3 1003 20 7
...
The "goods_in" table stores the records that all goods come into warehouse, the pid in this table is the same as in table "stock" which is the product ref code. There will be multiple records for each product in "goods_in" table.
The "stock" table stores all the SKU we are holding and the current stock level as well as the product cost.
What I'm trying to do is:
Group by pid AND date (Year+Month) from "goods_in" so I get sub-total number of goods booked-in in each month.
Multiple sub-total with stock.price.
Get total amount of above, something like SUMPRODUCT in excel.
Exports to html table or excel.
I've tried several answers from SO with GROUP BY/ROLLUP/JOIN, and apparently I haven't made it right as expected. I can make this simple if I just add a cost column to the "goods_in" table but that would make it untidy.
I'm still on my learning curves with MYSQL, forgive me if this looks simple to you guys.
Thanks.
Ken
Hard to know for sure what you want, but it sounds something like this:
select
pid,
year(in_date) as year,
month(in_date) as month,
sum(goods_in.in_num * stock.price)
from goods_in
join stock using (pid)
group by pid, year, month
For exporting to html or excel, you are best off asking a separate question.
I have a set of inventory data where the amount increases at a given rate. For example, the inventory increases by ten units every day. However, from time to time there will be an inventory reduction that could be any amount. I need a query that can find me the most recent inventory reduction and return to me the sum of that deduction.
My table holds date and amount for numerous item id's. In theory what I am trying to do is select all amounts and dates for a given item ID, and then find the difference between the most recent reduction between two days inventory. Due to the fact that multiple items are tracked, there is no guarantee that the id column will be consecutive for a set of items.
Researching to find a solution to this has been completely overwhelming. It seems like window functions might be a good route to try, but I have never used them and don't even really have a concept of where to start.
While I could easily return the amounts and do the calculation in PHP, I feel the right thing to do here is harness SQL but my experience with more complex queries is limited.
ID | ItemID | Date | Amount
1 2 2019-05-05 25
7 2 2019-05-06 26
34 2 2019-05-07 14
35 2 2019-05-08 15
67 2 2019-05-09 16
89 2 2019-05-10 5
105 2 2019-05-11 6
Given the data above, it would be nice to see a result like:
item id | date | reduction
2 2019-05-10 11
This is because the most recent inventory reduction is between id 67 and 89 and the amount of the reduction is 11 on May 10th 2019.
In MySQL 8+, you can use lag():
select t.*, (prev_amount - amount) as reduction
from (select t.*,
lag(amount) over (partition by itemid order by date) as prev_amount
from t
) t
where prev_amount > amount
order by date desc
limit 1;
I have a table inside my database just like the sample below and i would like to query the same data but in the Column 2 the positions of the data would be 1 row greater than the previous data.
P.S. Im actually making a system for a Electric Meter Reading and I need the Current(Column 1) and the Previous(Column 2) Data Reading, so that I could compute the total consumption of the Electric Meter. But I am having a hard time doing it. Any suggestions would be deeply appreciated. Thank You. :)
Example data:
Desired Query Output:
Keep in mind that SQL table rows have no inherent order. They're just bags of records.
You must order them based on some column value or other criterion. In your case I guess you want the most recent and the second most recent meter reading for each account. Presumably your reading table has columns something like this:
reading_id customer_id datestamp value
1 1122 2009-02-11 112
2 1234 2009-02-13 18
3 1122 2009-03-08 125
4 1234 2009-03-10 40
5 1122 2009-04-12 160
6 1234 2009-04-11 62
I guess you need this sort of result set
customer_id datestamp value previous
1122 2009-03-08 125 112
1122 2009-04-12 160 125
1234 ...etcetera.
How can you get this? For each row in the table, you need a way to find the previous reading for the same customer: that is, the row with
the same customer id
the latest datestamp that occurs before the current datestamp.
This is a job for a so-called correlated subquery. Here's the query, with its subquery. (https://www.db-fiddle.com/f/hWGAbq4uAbA5f15j7oZY9o/0)
SELECT aft.customer_id,
aft.datestamp,
( SELECT bef.value
FROM r bef /* row from table.... */
WHERE bef.datestamp < aft.datestamp /* with datestamp < present datestamp */
AND bef.customer_id = aft.customer_id /* and same customer id */
ORDER BY bef.datestamp DESC /* most recent first */
LIMIT 1 /* only most recent */
) prev,
aft.value
FROM r aft
ORDER BY aft.customer_id, aft.datestamp
Notice that dealing with the first reading for each customer takes some thought in your business process.
pnr mnd pris
1 1 600
1 7 900
2 1 600
2 7 600
3 1 40
3 7 40
I have trouble how to sum specific rows on the columns. Looking at the above, the table is called travel and it has 3 columns:
pnr - Personal Number
mnd - Month
Pris - Price
So what I want is to sum total of the price for the a specific month, so in this case, it should be 1240 USD and month 1. For the month 7, it should be 1540 USD.
I have trouble to do the query correct. So far from I have tried is this:
SELECT t.rnr, t.mnd, SUM(t.pris)
FROM travel AS t
WHERE t.mnd = 1
The result I get is 3720 USD which I have no idea how the SQL managed to calculate this for me.
Appreciate if someone could please help me out!
For this you need to drop the pnr column from the output (it is not relevant and will cause your data to split) and add a GROUP BY:
SELECT t.mnd, SUM(t.pris)
FROM travel AS t
WHERE t.mnd = 1
GROUP BY t.mnd
Live demo: https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=b34ec2bb9c077c2d74ffc66748c5c142
(The use of an aggregate function without grouping, as you've got now, is not a standard SQL feature and can often be turned off in MySQL. If turned on, you might not always get the result you expected/intended.)
just group your result with mnd column
SELECT t.mnd, SUM(t.pris)
FROM travel AS t
group by t.mnd