Add FORMAT_BYTES and FORMAT_NANO_TIME functions

TOC-tidb-cloud.md

@@ -590,6 +590,7 @@
       - [Sequence Functions](/functions-and-operators/sequence-functions.md)
       - [List of Expressions for Pushdown](/functions-and-operators/expressions-pushed-down.md)
       - [TiDB Specific Functions](/functions-and-operators/tidb-functions.md)
+      - [Utility Functions](/functions-and-operators/utility-functions.md)
     - [Clustered Indexes](/clustered-indexes.md)
     - [Constraints](/constraints.md)
     - [Generated Columns](/generated-columns.md)

TOC.md

@@ -971,6 +971,7 @@
       - [Sequence Functions](/functions-and-operators/sequence-functions.md)
       - [List of Expressions for Pushdown](/functions-and-operators/expressions-pushed-down.md)
       - [TiDB Specific Functions](/functions-and-operators/tidb-functions.md)
+      - [Utility Functions](/functions-and-operators/utility-functions.md)
       - [Comparisons between Functions and Syntax of Oracle and TiDB](/oracle-functions-to-tidb.md)
     - [Clustered Indexes](/clustered-indexes.md)
     - [Vector Index](/vector-search/vector-search-index.md)

functions-and-operators/utility-functions.md

@@ -0,0 +1,42 @@
+---
+title: Utility Functions
+summary: This document introduces utility functions supported in TiDB.
+---
+
+# Utility Functions
+
+This document introduces utility functions supported in TiDB
+
+## `FORMAT_BYTES()`
+
+The `FORMAT_BYTES()` function formats a number of bytes into a human-readable format for you.
+
+```sql
+SELECT FORMAT_BYTES(10*1024*1024);
+```
+
+```
++----------------------------+
+| FORMAT_BYTES(10*1024*1024) |
++----------------------------+
+| 10.00 MiB                  |
++----------------------------+
+1 row in set (0.001 sec)
+```
+
+## `FORMAT_NANO_TIME()`
+
+The `FORMAT_NANO_TIME()` function formats a number of nanoseconds as a human-readable number.
+
+```sql
+SELECT FORMAT_NANO_TIME(1000000);
+```
+
+```
++---------------------------+
+| FORMAT_NANO_TIME(1000000) |
++---------------------------+
+| 1.00 ms                   |
++---------------------------+
+1 row in set (0.001 sec)
+```