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Shaun StruwigandClaude Opus 4.8
584a980971
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
48 lines
2.1 KiB
Plaintext
48 lines
2.1 KiB
Plaintext
---
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description: 'Aggregates arrays into a larger array of those arrays.'
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keywords: ['groupArrayArray', 'array_concat_agg']
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slug: /sql-reference/aggregate-functions/reference/grouparrayarray
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title: 'groupArrayArray'
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doc_type: 'reference'
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---
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Aggregates arrays into a larger array of those arrays.
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Combines the [`groupArray`](/reference/functions/aggregate-functions/groupArray) function with the [Array](/reference/functions/aggregate-functions/combinators#-array) combinator.
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Alias: `array_concat_agg`
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**Example**
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We have data which captures user browsing sessions. Each session records the sequence of pages a specific user visited.
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We can use the `groupArrayArray` function to analyze the patterns of page visits for each user.
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```sql title="Setup"
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CREATE TABLE website_visits (
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user_id UInt32,
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session_id UInt32,
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page_visits Array(String)
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) ENGINE = Memory;
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INSERT INTO website_visits VALUES
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(101, 1, ['homepage', 'products', 'checkout']),
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(101, 2, ['search', 'product_details', 'contact']),
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(102, 1, ['homepage', 'about_us']),
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(101, 3, ['blog', 'homepage']),
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(102, 2, ['products', 'product_details', 'add_to_cart', 'checkout']);
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```
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```sql title="Query"
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SELECT
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user_id,
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groupArrayArray(page_visits) AS user_session_page_sequences
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FROM website_visits
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GROUP BY user_id;
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```
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```sql title="Response"
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┌─user_id─┬─user_session_page_sequences───────────────────────────────────────────────────────────────┐
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1. │ 101 │ ['homepage','products','checkout','search','product_details','contact','blog','homepage'] │
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2. │ 102 │ ['homepage','about_us','products','product_details','add_to_cart','checkout'] │
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└─────────┴───────────────────────────────────────────────────────────────────────────────────────────┘
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```
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