Purpose
information_schema.STATISTICS displays information about table indexes.
Fields
| Field | Type | Nullable? | Description |
|---|---|---|---|
| TABLE_CATALOG | varchar(3) | NO | The name of the catalog to which the table containing the column belongs. The value of this field is fixed to def. |
| TABLE_SCHEMA | varchar(128) | NO | The name of the database. |
| TABLE_NAME | varchar(128) | NO | The name of the table. |
| NON_UNIQUE | bigint(20) | NO | Indicates whether the index is unique. |
| INDEX_SCHEMA | varchar(128) | NO | The name of the database. |
| INDEX_NAME | varchar(128) | NO | The type of the index. |
| SEQ_IN_INDEX | bigint(20) | NO | The sequence number of the index. |
| COLUMN_NAME | varchar(128) | NO | The name of the column. |
| COLLATION | varchar(128) | YES | The name of the collation. |
| CARDINALITY | bigint(20) | YES | The estimate of the number of unique values in the index. |
| SUB_PART | varchar(256) | YES | The index prefix. That is, the number of indexed characters if the column is only partly indexed. The value is NULL if the entire column is indexed. |
| PACKED | varchar(256) | YES | Indicates how the key is packed. |
| NULLABLE | varchar(128) | NO | Indicates whether the index value can be NULL. |
| INDEX_TYPE | varchar(128) | NO | The data structure type used by the index. |
| COMMENT | varchar(4096) | YES | The comment. |
| INDEX_COMMENT | varchar(4096) | NO | The index comment. |
| IS_VISIBLE | varchar(3) | NO | Indicates whether the index is visible. |