Update ANY_VALUE aggregate function documentation (#2818)

* Update ANY_VALUE aggregate function documentation

- Make ANY_VALUE the primary function with comprehensive documentation
- Add redirect from old aggregate-any path to aggregate-any-value
- Remove duplicate aggregate-any.md file
- Include clear examples showing GROUP BY performance benefits
- Add version info (v1.2.815)

* Fix broken markdown link for ANY_VALUE function in aggregate index

Update reference from aggregate-any.md to aggregate-any-value.md to match
the updated filename, resolving build error.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

---------

Co-authored-by: Claude <[email protected]>

Author: BohuTANG

docs/en/sql-reference/20-sql-functions/07-aggregate-functions/aggregate-any-value.md

@@ -0,0 +1,79 @@
+---
+title: ANY_VALUE
+---
+import FunctionDescription from '@site/src/components/FunctionDescription';
+
+<FunctionDescription description="Introduced or updated: v1.2.815"/>
+
+Aggregate function.
+
+The `ANY_VALUE()` function returns an arbitrary non-NULL value from the input expression. It's used in `GROUP BY` queries when you need to select a column that isn't grouped or aggregated.
+
+> **Alias:** `ANY()` returns the same result as `ANY_VALUE()` and remains available for compatibility.
+
+## Syntax
+
+```sql
+ANY_VALUE(<expr>)
+```
+
+## Arguments
+
+| Arguments | Description    |
+|-----------|----------------|
+| `<expr>`  | Any expression |
+
+## Return Type
+
+The type of `<expr>`. If all values are NULL, the return value is NULL.
+
+:::note
+- `ANY_VALUE()` is non-deterministic and may return different values across executions.
+- For predictable results, use `MIN()` or `MAX()` instead.
+:::
+
+## Example
+
+**Sample Data:**
+```sql
+CREATE TABLE sales (
+  region VARCHAR,
+  manager VARCHAR,
+  sales_amount DECIMAL(10, 2)
+);
+
+INSERT INTO sales VALUES
+  ('North', 'Alice', 15000.00),
+  ('North', 'Alice', 12000.00),
+  ('South', 'Bob', 20000.00);
+```
+
+**Problem:** This query fails because `manager` isn't in GROUP BY:
+```sql
+SELECT region, manager, SUM(sales_amount)  -- ❌ Error
+FROM sales GROUP BY region;
+```
+
+**Old approach:** Add `manager` to GROUP BY, but this creates more groups than needed and hurts performance:
+```sql
+SELECT region, manager, SUM(sales_amount)
+FROM sales GROUP BY region, manager;  -- ❌ Poor performance due to extra grouping
+```
+
+**Better solution:** Use `ANY_VALUE()` to select the manager:
+```sql
+SELECT
+  region,
+  ANY_VALUE(manager) AS manager,  -- ✅ Works
+  SUM(sales_amount) AS total_sales
+FROM sales
+GROUP BY region;
+```
+
+**Result:**
+```text
+| region | manager | total_sales |
+|--------|---------|-------------|
+| North  | Alice   | 27000.00    |
+| South  | Bob     | 20000.00    |
+```

docs/en/sql-reference/20-sql-functions/07-aggregate-functions/aggregate-any.md

@@ -15,7 +15,7 @@ This page provides a comprehensive overview of aggregate functions in Databend,
 | [AVG](aggregate-avg.md) | Calculates the average of values | `AVG(temperature)` → `72.5` |
 | [MIN](aggregate-min.md) | Returns the minimum value | `MIN(price)` → `9.99` |
 | [MAX](aggregate-max.md) | Returns the maximum value | `MAX(price)` → `99.99` |
-| [ANY](aggregate-any.md) | Returns any value from the group | `ANY(status)` → `'active'` |
+| [ANY_VALUE](aggregate-any-value.md) | Returns any value from the group | `ANY_VALUE(status)` → `'active'` |
 
 ## Conditional Aggregation
 

docs/en/sql-reference/20-sql-functions/07-aggregate-functions/index.md

@@ -429,6 +429,11 @@ const siteRedirects = [
   {
     from: '/guides/query/dictionary',
     to: '/guides/query/advanced/'
+  },
+  // ANY function redirect to ANY_VALUE
+  {
+    from: '/sql/sql-functions/aggregate-functions/aggregate-any',
+    to: '/sql/sql-functions/aggregate-functions/aggregate-any-value'
   }
 ];
 export default siteRedirects;