ref-docs: sql: add WITH ZONE option to SHOW RANGES

src/current/v26.1/functions.md

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+---
+title: sql: add WITH ZONE option to SHOW RANGES
+summary: Built-in Function Reference
+toc: true
+docs_area: reference.sql
+---
+
+# Built-in Function Reference
+
+## `crdb_internal.zone_config_for_key()`
+
+**Category**: System info
+
+**Signature**: `crdb_internal.zone_config_for_key(key BYTES) → JSONB`
+
+**Description**: Returns the fully resolved zone configuration for the range that contains the given key as a JSONB object. The zone configuration includes inheritance from parent zones (e.g., table → database → RANGE DEFAULT). This function is primarily used by `SHOW RANGES WITH ZONE` to display the effective zone configuration for each range.
+
+**Example**:
+```sql
+-- Get zone config for a specific table's key span
+SELECT crdb_internal.zone_config_for_key(crdb_internal.table_span(12345)[1]);
+
+-- Extract the number of replicas from the zone config
+SELECT crdb_internal.zone_config_for_key(crdb_internal.table_span(12345)[1])->>'numReplicas';
+
+-- Use with SHOW RANGES WITH ZONE
+SELECT start_key, zone_config->>'numReplicas' AS replicas 
+FROM [SHOW CLUSTER RANGES WITH ZONE] 
+LIMIT 5;
+```
+
+## `crdb_internal.zone_config_span_end()`
+
+**Category**: System info
+
+**Signature**: `crdb_internal.zone_config_span_end(key BYTES) → BYTES`
+
+**Description**: Returns the end key of the zone config span that the given key belongs to. For named zones (meta, liveness, timeseries, system, tenants), this returns the next static split point. For table zones, this returns the narrowest applicable boundary: either the next subzone split point within the table (for index/partition-level zone configs) or the table's key span end if no subzone boundaries exist.
+
+**Example**:
+```sql
+-- Get the zone config span end for a table's start key
+SELECT crdb_internal.zone_config_span_end(crdb_internal.table_span(12345)[1]);
+
+-- Check if a table's zone config span matches its key span
+SELECT crdb_internal.zone_config_span_end(crdb_internal.table_span(12345)[1]) = crdb_internal.table_span(12345)[2];
+
+-- Use with SHOW RANGES WITH ZONE to see zone conformance
+SELECT start_key, zone_config_conformant 
+FROM [SHOW CLUSTER RANGES WITH ZONE] 
+WHERE NOT zone_config_conformant;
+```