Create current-catalog.md

Author: soyeric128

docs/en/sql-reference/20-sql-functions/15-context-functions/current-catalog.md

@@ -0,0 +1,26 @@
+---
+title: CURRENT_CATALOG
+---
+import FunctionDescription from '@site/src/components/FunctionDescription';
+
+<FunctionDescription description="Introduced or updated: v1.2.668"/>
+
+Returns the name of the catalog currently in use for the session.
+
+## Syntax
+
+```sql
+CURRENT_CATALOG()
+```
+
+## Examples
+
+```sql
+SELECT CURRENT_CATALOG();
+
+┌───────────────────┐
+│ current_catalog() │
+├───────────────────┤
+│ default           │
+└───────────────────┘
+```