Is it possible to use column name as variable in Kusto? - azure-data-explorer

In Kusto, can I do this?
let my_var = "prefix";
let my_custom_col = strcat(my_var, "_something");
my_tab | extend my_custom_col = "5"
I tried it but it creates a column with name, my_custom_col not with the name prefix_something.
Is it possible to use a variable as a column name in Kusto?

you can use columnifexist function
https://learn.microsoft.com/en-us/azure/data-explorer/kusto/query/columnifexists

This is not currently possible in Kusto.

It's not very tidy, but you can do with with bag_unpack.
let _column_name = 'Column name';
print 'test'
| project _bag = bag_pack(_column_name, State)
| evaluate bag_unpack(_bag)
bag_unpack docs: https://learn.microsoft.com/en-us/azure/data-explorer/kusto/query/bag-unpackplugin

Related

Progess 4GL - How to filter multiple records using AND operator in one table field?

I want to check and filter only if the table has value1 = 005 and value1 = 009. But it seems below query is not helping me. I dont know where I am making mistakes. Kindly help to solve this. Note - I cannot use where not as it may have many different value stored in value1 field
DEFINE TEMP-TABLE test NO-UNDO
FIELD value1 AS CHARACTER
.
EMPTY TEMP-TABLE test.
CREATE test.
ASSIGN
value1 = "005".
CREATE test.
ASSIGN
value1 = "009".
CREATE test.
ASSIGN
value1 = "001".
FOR EACH test NO-LOCK
WHERE value1 <> ""
AND (value1 = "005" AND value1 = "009")
:
MESSAGE YES.
END.
You can use can-find
if can-find(first test WHERE value1 = "005")
AND can-find(first test WHERE value1 = "009")
then message yes.
It is safest to always use can-find(first if you're looking for a non-unique value
It looks like you're looking for an OR ooperation, rather than AND.
If you want to check if both records are present you could do :
DEFINE VARIABLE isPresent005 AS LOGICAL NO-UNDO.
DEFINE VARIABLE isPresent009 AS LOGICAL NO-UNDO.
DEFINE VARIABLE bothPresents AS LOGICAL NO-UNDO.
FIND FIRST test WHERE test.value1 = "005" NO-LOCK NO-ERROR.
isPresent005 = AVAIL test.
FIND FIRST test WHERE test.value1 = "009" NO-LOCK NO-ERROR.
isPresent009 = AVAIL test.
bothPresents = isPresent005 AND isPresent009.
But, if you only want to get these 2 records, you should use OR :
FOR EACH test WHERE test.value1 = "005" OR test.value1 = "009" NO-LOCK :
/*do stuff*/
END.
Another option if you are, maybe, looking for some additional fields might look something like this:
define buffer test005 for test.
define buffer test009 for test.
for each test005 no-lock where test005.customer = 1 and test005.value1 = "005",
each test009 no-lock where test009.customer = 1 and test009.value1 = "009":
display test005.customer.
end.
Use OR instead of AND to search the records...
This will return records if value1 = 005 OR value1 = 009.
FOR EACH test NO-LOCK
WHERE value1 <> ""
AND (value1 = "005" OR value1 = "009")
:
MESSAGE YES.
END.
Is not possible to search using your way, because value1 cannot be two values at once, it's always one OR another.

Kusto Query Dynamic sort Order

I have started working on Azure Data Explorer( Kusto) recently.
My requirement to make sorting order of Kusto table in dynamic way.
// Variable declaration
let SortColumn ="run_date";
let OrderBy="desc";
// Actual Code
tblOleMeasurments
| take 10
|distinct column1,column2,column3,run_date
|order by SortColumn OrderBy
Here My code working fine till Sortcolumn but when I tried to add [OrderBy] after [SortColumn] kusto gives me error .
My requirement here is to pass Asc/desc value from Variable [OrderBy].
Kindly assist here with workarounds and solutions which help me .
The sort column and order cannot be an expression, it must be a literal ("asc" or "desc"). If you want to pass the sort column and sort order as a variable, create a union instead where the filter on the variables results with the desired outcome. Here is an example:
let OrderBy = "desc";
let sortColumn = "run_date";
let Query = tblOleMeasurments | take 10 |distinct column1,column2,column3,run_date;
union
(Query | where OrderBy == "desc" and sortColumn == "run_date" | order by run_date desc),
(Query | where OrderBy == "asc" and sortColumn == "run_date" | order by run_date asc)
The number of union legs would be the product of the number of candidate sort columns times two (the two sort order options).
An alternative would be sorting by a calculated column, which is based on your sort_order and sort_column. The example below works for numeric columns
let T = range x from 1 to 5 step 1 | extend y = -10 * x;
let sort_order = "asc";
let sort_column = "y";
T
| order by column_ifexists(sort_column, "") * case(sort_order == "asc", -1, 1)

Kusto Query Language: How to save column of results into a variable?

Lets say I have a query like:
cluster("cluster1").database("db2").Table3
| distinct * // distinct combinations of data
| take 5 // take 5
How do I save the values from a column in the results output to a pack_array variable.
I want to use this pack_array variable for follow on queries like:
cluster("cluster2").database("db3").Table1
| where ColumnofInterest in (pack_array_var from above)
| take 5 // take 5
Provide the "*" argument to the function and use the "let" statement. Here is an example:
let ValuesFromTheOtherCluster = cluster('cluster1').database('db2').Table3
| extend tempArray = pack_array(*)
| summarize filters = make_set(tempArray);
cluster('cluster2').database("db3").Table1
| where ColumnofInterest in (ValuesFromTheOtherCluster)

Kusto result column name, bin value from request_parameters

Using query_parameters, how can I:
specify a result column name (ex: summarize ResultColumnName = count())
specify the value of a bin, when value is actually the name of a column in the table
This is easiest to summarize with an example:
let myTable = datatable (Timestamp:datetime)
[datetime(1910-06-11),
datetime(1930-01-01),
datetime(1997-06-25),
datetime(1997-06-25)];
let UntrustedUserInput_ColumnName = "MyCount"; // actually from query_parameters
let UntrustedUserInput_BinValue = "Timestamp"; // actually from query_parameters
let UntrustedUserInput_BinRoundTo = "365d"; // actually from query_parameters
// the query I really want to perform
myTable
| summarize MyCount=count() by bin(todatetime(Timestamp), totimespan(365d));
// what the query looks like if I use query_parameters
myTable
| summarize UntrustedUserInput_ColumnName=count() by bin(todatetime(UntrustedUserInput_BinValue), totimespan(UntrustedUserInput_BinRoundTo));
Results:
Timestamp MyCount
--------- -------
1909-09-26T00:00:00Z 1
1929-09-21T00:00:00Z 1
1996-09-04T00:00:00Z 2
Column1 UntrustedUserInput_ColumnName
------- -----------------------------
4
I can't find a solution to #1.
It appears #2 can almost be solved by using column_ifexists, but I don't have a "default" to fall back on, I'd rather just fail if the column doesn't exist.
Treating column names as variables is not possible since columns names are part of the result schema coming out of each operator (with the exception of the "evaluate" operator, see specifically the pivot plugin).
There actually is a way to set variable names to a column, using a hacky trick:
let VariableColumnName = "TestColumn"; // the new column name that you want
range i from 1 to 5 step 1 // this is just a sample query
| project pack(VariableColumnName, i) // this created a JSON
| evaluate bag_unpack(Column1) // unpacking the JSON creates a column with a dynamic name
This will return a column named TestColumn, which is set in VariableColumnName.

How to retreive custom property corresponding to another property in azure

I am trying to write a kusto query to retrieve a custom property as below.
I want to retrieve count of pkgName and corresponding organization. I could retrieve the count of pkgName and the code is attached below.
let mainTable = union customEvents
| extend name =replace("\n", "", name)
| where iif('*' in ("*"), 1 == 1, name in ("*"))
| where true;
let queryTable = mainTable;
let cohortedTable = queryTable
| extend dimension = customDimensions["pkgName"]
| extend dimension = iif(isempty(dimension), "<undefined>", dimension)
| summarize hll = hll(itemId) by tostring(dimension)
| extend Events = dcount_hll(hll)
| order by Events desc
| serialize rank = row_number()
| extend dimension = iff(rank > 10, 'Other', dimension)
| summarize merged = hll_merge(hll) by tostring(dimension)
| project ['pkgName'] = dimension, Counts = dcount_hll(merged);
cohortedTable
Please help me to get the organization along with each pkgName projected.
Please try this simple query:
customEvents
| summarize counts=count(tostring(customDimensions.pkgName)) by pkgName=tostring(customDimensions.pkgName),organization=tostring(customDimensions.organization)
Please feel free to modify it to meet your requirement.
If the above does not meet your requirement, please try to create another table which contains pkgName and organization relationship. Then use join operator to join these tables. For example:
//create a table which contains the relationship
let temptable = customEvents
| summarize by pkgName=tostring(customDimensions.pkgName),organization=tostring(customDimensions.organization);
//then use the join operator to join these tables on the keyword pkgName.

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