I was trying to write a simple FluxQL Query in Grafana Dashboard that uses a variable
m1(of type constant)(which contains the name of the measurement)
I created the variable m1 in grafana dashboard variables
m1 = my-measurement
and tried to run the following queries but non of them worked and they either say expression request error or No Data)
i.e
SELECT count("fails") FROM "/^${m1:raw}$/"
SELECT count("fails") FROM "/^${m1}$/"
SELECT count("fails") FROM $m1" (expression request error)
SELECT count("fails") FROM "$m1"
SELECT count("fails") FROM "${m1}"
The only query worked was without dashboard variables
SELECT count("fails") FROM "my-measurement"
How can I use the variables to work for that query.
On the similar ground I tried to make a custom variable(myVar) for which we take integer input values from user and on that basis where clause should work, but same error occurs either no data or expression request error
What I tried was
SELECT count(*) from "my-measurement-2" WHERE ("value" > $myVar)
How should I solve these issues?Please help
You may have a problem with
1.) syntax
SELECT count("fails")
FROM "${m1:raw}"
2.) data
You may correct query syntax, but query can be very inefficient. Query execution may need a lot of time - so it's better to have timefilter, which will use selected dashboard time range (make sure you have some data in that time range)
SELECT count("fails")
FROM "${m1:raw}"
WHERE $timeFilter
3.) Grafana panel configuration
Make sure you are using suitable panel - for query above Stat panel is a good option (that query returns only single value, not timeseries, so time series panel types may have a problem with that).
Generally, use query inspector to see how are variables interpolated - there can be "magic", which is not obvious - e.g. quotes which are added around numeric variables, so then it is string filtering and not numeric filtering on the InfluxDB level.
Related
Is there any way to delete columns of an influx timeseries as we have accidentally injected data using the wrong data type (int instead of float).
Or to change the type of data instead.
Unfortunately, there is no way to delete a "column" (i.e. a tag or a field) from an Influx measurement so far. Here's the feature request for that but there is no ETA yet.
Three workarounds:
use SELECT INTO to copy the desirable data into a different measurement, excluding the undesirable "columns". e.g.:
SELECT desirableTag1, desirableTag2, desirableField1, desirableField2 INTO new_measurement FROM measurement
use CAST operations to "change the data type" from float to int. e.g.:
SELECT desirableTag1, desirableTag2, desirableField1, desirableField2, undesiredableTag3::integer, undesiredableField3::integer INTO new_measurement FROM measurement
"Update" the data with insert statement, which will overwrite the data with the same timestamp, same tags, same field keys. Keep all other things equal, except that the "columns" that you would like to update. To make the data in integer data type, remember to put a trailing i on the number. Example: 42i. e.g.:
insert measurement,desirableTag1=v1 desirableField1=fv1,desirableField2=fv2,undesirableField1=someValueA-i 1505799797664800000
insert measurement,desirableTag1=v21 desirableField1=fv21,desirableField2=fv22,undesirableField1=someValueB-i 1505799797664800000
I've a query that uses difference function and I can't understand why it returns no data.
The query is:
SELECT
difference(FIRST(grid_power_counter)) as grid_power_consumed
FROM homesolar.origin.main GROUP BY time(15m)
If I remove the difference function it returns data:
SELECT
FIRST(grid_power_counter) as grid_power_consumed
FROM homesolar.origin.main GROUP BY time(15m)
Also, I can get results if I add a where time > now()-24h to the select with difference function.
I really can't understand that behavior. Can someone help me?
Q: My query would only work if I add the where filter to it. Why is that so?
Quoted from influxdb's Groupby time doc:
Basic GROUP BY time() queries require an InfluxQL function in the
SELECT clause and a time range in the WHERE clause.
I suspect your first DIFFERENCE query didn't work because it was missing the mandatory WHERE filter for the Groupby time(...) function.
The Group by time() clause could be returning no rows and hence not.
This could potentially be a github issue for the influx team as I think their query parser should be complaining to you about the missing where filter for Group by time.
References:
https://docs.influxdata.com/influxdb/v1.5/query_language/data_exploration/#the-group-by-clause
I have a following issue:
I need to calculate difference between consecutive points where some arbitrary ID is equal. The following:
SELECT difference(value_field) FROM mesurementName WHERE "IdField" = '10'
Works, returns difference between each consecutive point with IdField BUT IdField is lost (only time is propagated to query result). In my case time is not unique (i.e. measurement may contain many points with same timestamp, but different IdField). So I tried:
SELECT difference(value_field), IdField FROM mesurementName WHERE "IdField" = '10'
which yields:
error parsing query: mixing aggregate and non-aggregate queries is not supported!!
My next attempt was using sub-query:
SELECT IdField, diff
FROM (
SELECT
difference(flow_val) as diff
FROM
mesurementA
WHERE "IdField" = '10'
)
Which resulted in always null value in IdField.
I'd like to ask you for help or suggestion how to solve issue. By the way, we are using InfluxDB 1.3, which is not supporting JOIN anymore
If anyone would stuck as I was, then solution is following:
SELECT difference(value_field) FROM mesurementName GROUP BY "IdField"
Above somehow implicitly add "IdField" to result series and is propagated to resulting measurements with INTO clause
I'm using SPSS modeler and I have a variable that the software recognizes as numeric. So the missing values are $null$. I want that the missing values of the variable are selectionable with '', as character.
So I would: or trasform the format of the variable from numeric to character or change only the missing values from $null$ to ''.
How can I fix?
thanks in advance
The best way to select null values in a numeric field is to use the #NULL() function from the Blanks and Null section of the Expression Builder.
For example, if you wanted to keep only the null values so that you could inspect them, you might use a Select node. Leave the radio button set as Include. Press the Expression Builder (calculator) button. Change the filter in the drop menu on the left side from General Functions to show Blanks and Null (press B 2 or 3 times). Double-click on #NULL(ITEM). Go to the right side and double-click on your numeric field name. Put a Table node at the end and run it.
Using Select #NULL in IBM SPSS Modeler
Another way to view just the null rows is to enter the #NULL(varname) function into the "Highlight records where" section of the Table dialog box.
"Highlight records where" dialog
When you run the table, any row that is true for this condition will be shown in red.
If you really need the variable to be a string, then use a Compute node to create a copy of this field under a new name and use the to_string() function in the Conversion section of the Expression Builder to change the type of the variable. Now you will be able to use the the Select node to grab "" as the missing value. Or you could use the Filler node to replace the column, but then you would not be able to compare before and after.
The dialog examples shown in this answer use this sample stream that is installed with your IBM SPSS Modeler software:
C:\Program Files\IBM\SPSS\Modeler\18.0\Demos\streams\featureselection.str
The easiest way to do it it's using the Fill node with the configurations:
A) FIELD
B) Condition = #NULL(#FIELD)
C) Replace by = ' '
This node will replace all $null$ for ' ' at the same variable chosen in option a.
I don't think you can customize how you visualize $nulls. (I know it's possible in SQL db though)
So I'd suggest that you work with the numbers and when you want to visualize or export the results, then turn the field to a string one then replace nulls:
Filled node > to_string(#FIELD)
Filler node > blank and nulls > #FIELD = ''
I'm writing a delphi(7 ver) application and in some place I want to execute parameterized queries (for BDE and Paradox) which will be loaded at runtime into a TQuery by the user. These queries will be stored in text files (one text file for one query). The application then, will construct for any parameter of the query, one input control (Tedit) in order to be able to accept values by the user. Also there will be a button for the execution of query. My question is how can I recognize the datatype of the query's parameter? Is there a way to get this type without of cause to be included in some way in the text file containing the query?
Create a second query from the first, but modify its where clause to ensure no rows.
SELECT * FROM MYTABLE WHERE PKFIELD IS NULL
Name your parameters so that you can establish their datatypes from the fieldtypes of this second query.
I realise this only works for relatively simple cases, but it should get you some of the way.
the advantage of using a parameter is that you don't need to know its data type.
Use the string value from the tedit
"select * from mytable where myfield = :param1"
"parambyname('param1').asstring := edit1.text"
I've made this with MySQL database. you must define some parameters, Exemple:
SELECT * FROM MyTable WHERE MyField=[ANNEE];
in this case, i have an other table, called balise, that look like this
"ID" "BALISE" "CAPTION" "DEFAULT_VALUE" "CNDT" "COMPOSANT"
"1" "ANNEE" "Année" "2014" "Properties.MaxValue=2014||Properties.MinValue=2007" 1;
in runtime, this mean that:
Make in my Panel, a TLablel that have caption Année
Make in the same line an other component type 1 (That mean in my case TcxSpinEdit), this component have défault value 2014, have Two properties Max Value=2014 and Min Value=2007, (I use RTTI to modifie this value of parameters, in Delphi ver7, use TypeInfo).
An Other Button with function called Actualise, this function have Original query, must browse an array of TBalise that i have created, take the value (In my case, take TcxSpinEdit(MyObject).Value), and replace it in the copy of my query (AnsiReplaceStr(Requete, '[ANNEE]', MyValue)), so i have the final query to execute it.
I have module in complete projet, worked with this methode, and it workk fine.