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https://issues.apache.org/jira/browse/FLINK-32261?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17741203#comment-17741203
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Hanyu Zheng edited comment on FLINK-32261 at 7/8/23 2:26 AM:
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[~Sergey Nuyanzin] I think it's a good suggestion. It's good idea to support
varargs. By the way, can you help me to polish new description of this function?
{code:java}
Returns a map created by merging at least one map. These maps should have a
common map type. If there are overlapping keys, the value from 'map2' will
overwrite the value from 'map1', the value from 'map3' will overwrite the value
from 'map2', the value from 'mapn' will overwrite the value from 'map(n-1)'. If
any of maps is null, return null.{code}
was (Author: JIRAUSER300701):
[~Sergey Nuyanzin] I think it's a good suggestion. It's good idea to support
varargs. By the way, can you help me to polish new description of this function?
> Add MAP_UNION support in SQL & Table API
> ----------------------------------------
>
> Key: FLINK-32261
> URL: https://issues.apache.org/jira/browse/FLINK-32261
> Project: Flink
> Issue Type: Improvement
> Components: Table SQL / Planner
> Affects Versions: 1.18.0
> Reporter: Bonnie Varghese
> Assignee: Hanyu Zheng
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.18.0
>
>
> Description:
> This is an implementation of MAP_UNION
> Returns a map created by merging two maps, 'map1' and 'map2'. This two maps
> should have same data structure. If there are overlapping keys, the value
> from 'map2' will overwrite the value from 'map1'. If any of maps are null,
> return null.
> Syntax:
> {code:java}
> MAP_UNION(map1, map2){code}
> Arguments:
> * map1:The first map to be merged.
> * map2:The second map to be merged.
> Returns: A new map that contains the combined key-value pairs from {{map1}}
> and map{{{}2{}}}. If there are any overlapping keys, the value from {{map2}}
> will overwrite the value from {{{}map1{}}}.
> Examples:
> Merging maps with unique keys:
>
> {code:java}
> map1 = ['a': 1, 'b': 2] map2 = ['c': 3, 'd': 4]
> map_union[map1, map2]
> Output: ['a': 1, 'b': 2, 'c': 3, 'd': 4]{code}
> Merging maps with overlapping keys:
>
>
> {code:java}
> map1 = ['a': 1, 'b': 2] map2 = ['b': 3, 'c': 4]
> map_union[map1, map2]
> Output: ['a': 1, 'b': 3, 'c': 4]{code}
> See also:
> prestodb: [https://prestodb.io/docs/current/functions/aggregate.html]
>
>
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