ClickHouse/docs/en/sql-reference/aggregate-functions/reference/maxmap.md
Ivan Blinkov 7170f3c534
[docs] split aggregate function and system table references (#11742)
* prefer relative links from root

* wip

* split aggregate function reference

* split system tables
2020-06-18 11:24:31 +03:00

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---
toc_priority: 143
---
# maxMap {#agg_functions-maxmap}
Syntax: `maxMap(key, value)` or `maxMap(Tuple(key, value))`
Calculates the maximum from `value` array according to the keys specified in the key array.
Passing tuple of keys and values arrays is synonymical to passing two arrays of keys and values.
The number of elements in key and value must be the same for each row that is totaled.
Returns a tuple of two arrays: keys in sorted order, and values calculated for the corresponding keys.
Example:
``` sql
SELECT maxMap(a, b)
FROM values('a Array(Int32), b Array(Int64)', ([1, 2], [2, 2]), ([2, 3], [1, 1]))
```
``` text
┌─maxMap(a, b)──────┐
│ ([1,2,3],[2,2,1]) │
└───────────────────┘
```