---
title: "Statistics Information Functions"
id: functions-statistics
pg_version: "20devel"
---

<a id="functions-statistics"></a>

## 9.32. Statistics Information Functions

PostgreSQL provides a function to inspect complex statistics defined using the `CREATE STATISTICS` command. 

<a id="functions-statistics-mcv"></a>

### 9.32.1. Inspecting MCV Lists

```
pg_mcv_list_items ( pg_mcv_list ) setof record
```

`pg_mcv_list_items` returns a set of records describing all items stored in a multi-column MCV list. It returns the following columns: | Name | Type | Description | 
| --- | --- | --- |
| `index` | `integer` | index of the item in the MCV list | 
| `values` | `text[]` | values stored in the MCV item | 
| `nulls` | `boolean[]` | flags identifying `NULL` values | 
| `frequency` | `double precision` | frequency of this MCV item | 
| `base_frequency` | `double precision` | base frequency of this MCV item | 

 

The `pg_mcv_list_items` function can be used like this: 
SELECT m.* FROM pg_statistic_ext join pg_statistic_ext_data on (oid = stxoid),
                pg_mcv_list_items(stxdmcv) m WHERE stxname = 'stts';
 Values of the `pg_mcv_list` type can be obtained only from the pg_statistic_ext_data.`stxdmcv` column.