[ARROW-12710] [C++] String concatenate aggregate kernel

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: C++
• Labels: kernel
• External issue URL: https://github.com/apache/arrow/issues/28454
• Assignee: Unassigned
• Reporter: Ian Cook
• Created: 10/May/21 14:19
• Updated: 11/Jan/23 08:28

Description

Like MySQL/Impala group_concat and PostgreSQL string_agg. Takes a string array and a separator (possibly optional?) and returns one scalar string (one per group in the case of group aggregation) representing all the string values in the array concatenated together, with the separator added between each pair of concatenated values.

For example, in the case of no grouping and using separator "-", this would take input:

Array<string>
[ 
  "foo",
  "bar",
  "baz"
]

and return the following string scalar as output:

"foo-bar-baz"

 

Issue Links

• is a child of: ARROW-555 [C++] String algorithm library for StringArray/BinaryArray
• is a child of: ARROW-13339 [C++] Implement hash_aggregate kernels (umbrella issue)
• is blocked by: ARROW-12873 [C++][Compute] Support tagging ExecBatches with arbitrary extra information
• is depended upon by: ARROW-12711 [R] Bindings for paste(collapse), str_c(collapse), and str_flatten()