topic Re: How to convert array to String in DQL

How to convert array to String

deni — Sun, 17 Aug 2025 12:01:24 GMT

Hi,

From one of the tasks of the DQL course in university:

Data Types

Starting with the below DQL Query, what data type are the following fields:

related_entity_ids
dt.davis.is_duplicate
event.start

Afterwards, modify the query to cast the k8s.container.name field to a String.

I checked the requested types and the type of the k8s.container.name is an array. I tried the following:

fetch events | filter event.kind == "DAVIS_PROBLEM" | fields k8s.container.name | filterOut isNull(k8s.container.name) | fieldsAdd test = asString(k8s.container.name)

The value of the test column is null. I searched in the documentation, but didn't find anything like arrayToString(arr, delimiter) or similar.

Can you help me with this?

Regards, Deni

Re: How to convert array to String

krzysztof_hoja — Sun, 17 Aug 2025 18:04:45 GMT

Unfortunately there is no function where you can specify new delimiter. There is however toString function. This example should explain how it works and how to achieve what you need:

data record(arr=array("s1","s2","s3")) | fieldsAdd merged = toString(arr) | fieldsAdd merged2 = replaceString(merged,"""["""","") | fieldsAdd merged2 = replaceString(merged2,""""]""","") | fieldsAdd merged2 = replaceString(merged2,"""", """","/")

Re: How to convert array to String

deni — Sun, 17 Aug 2025 18:54:41 GMT

Ahaaa, I tried asString, but now I see in the documentation that all as... functions just verify the type and return null otherwise. If I want to cast, I need to use the to... functions — in this case toString.

Thanks also for the extra tips on how to set a custom delimiter 🙂