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> Calculates the maximum from `value` array according to the keys specified in the `key` array.

# maxMap

<h2 id="maxMappedArrays">
  maxMappedArrays
</h2>

Introduced in: v20.5.0

Calculates the maximum from `value` array according to the keys specified in the `key` array.

<Note>
  * Passing a tuple of keys and value arrays is identical to passing an array of keys and an array of values.
  * The number of elements in `key` and `value` must be the same for each row that is totaled.
</Note>

**Syntax**

```sql theme={null}
maxMappedArrays(key, value)
maxMappedArrays(Tuple(key, value))
```

**Arguments**

* `key` — Array of keys. [`Array(T)`](/reference/data-types/array)
* `value` — Array of values. [`Array(T)`](/reference/data-types/array)

**Returned value**

Returns a tuple of two arrays: keys in sorted order, and values calculated for the corresponding keys. [`Tuple(Array(T), Array(T))`](/reference/data-types/tuple)

**Examples**

**Usage example**

```sql title=Query theme={null}
SELECT maxMappedArrays(a, b)
FROM VALUES('a Array(Char), b Array(Int64)', (['x', 'y'], [2, 2]), (['y', 'z'], [3, 1]));
```

```response title=Response theme={null}
┌─maxMappedArrays(a, b)───┐
│ (['x','y','z'],[2,3,1]) │
└─────────────────────────┘
```