# Create new field based on existing fields from dataset

**URL:** <https://community.dremio.com/t/create-new-field-based-on-existing-fields-from-dataset/5972>\
**Category:** Uncategorized\
**Created:** [July 23, 2020, 2:24pm UTC](https://community.dremio.com/t/create-new-field-based-on-existing-fields-from-dataset/5972 "2020-07-23T14:24:34Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![nick.prusov](https://sea2.discourse-cdn.com/flex020/user_avatar/community.dremio.com/nick.prusov/32/2683_2.png) [@nick.prusov](https://community.dremio.com/u/nick.prusov)\
**Post date:** [July 23, 2020, 2:24pm UTC](https://community.dremio.com/t/create-new-field-based-on-existing-fields-from-dataset/5972/1 "2020-07-23T14:24:34Z")

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How can I create new filed with type Map using values from existing fields. For instance I have fields client\_name, client\_id. I would like to create new field client:  
{ “source\_system\_client\_id” : “client\_id”, “name”: “client\_name”}

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**Author:** ![balaji.ramaswamy](https://sea2.discourse-cdn.com/flex020/user_avatar/community.dremio.com/balaji.ramaswamy/32/843_2.png) [@balaji.ramaswamy](https://community.dremio.com/u/balaji.ramaswamy)\
**Post date:** [July 25, 2020, 7:34am UTC](https://community.dremio.com/t/create-new-field-based-on-existing-fields-from-dataset/5972/2 "2020-07-25T07:34:39Z")

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@nick.prusov

Currently Dremio only supports STRUCT or LIST complex data types

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<div class="post-metadata">

**Author:** ![nick.prusov](https://sea2.discourse-cdn.com/flex020/user_avatar/community.dremio.com/nick.prusov/32/2683_2.png) [@nick.prusov](https://community.dremio.com/u/nick.prusov)\
**Post date:** [July 25, 2020, 12:12pm UTC](https://community.dremio.com/t/create-new-field-based-on-existing-fields-from-dataset/5972/3 "2020-07-25T12:12:16Z")

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> [@nick.prusov](#):
>
> { “source\_system\_client\_id” : “client\_id”, “name”: “client\_name”}

How can I create similar structure type { “source\_system\_client\_id” : “client\_id”, “name”: “client\_name”}  
using STRUCT or LIST data types based on available fields in dataset client\_id, client\_name