statistics
statistics provides information about table indexes.
The following fields are provided in statistics:
| Field | Description |
|---|---|
| TABLE_CATALOG | The name of the catalog to which the table containing the index belongs. This value is always def. |
| TABLE_SCHEMA | The name of the database to which the table containing the index belongs. |
| TABLE_NAME | The name of the table containing the index. |
| NON_UNIQUE | 0 if the index cannot contain duplicates, 1 if it can. |
| INDEX_SCHEMA | The name of the database to which the index belongs. |
| INDEX_NAME | The name of the index. If the index is the primary key, the name is always PRIMARY. |
| SEQ_IN_INDEX | The column sequence number in the index, starting with 1. |
| COLUMN_NAME | The column name. See also the description for the EXPRESSION column. |
| COLLATION | How the column is sorted in the index. This can have values A (ascending), D (descending), or NULL (not sorted). |
| CARDINALITY | An estimate of the number of unique values in the index. |
| SUB_PART | The index prefix. That is, the number of indexed characters if the column is only partly indexed, NULL if the entire column is indexed. |
| PACKED | Indicates how the key is packed. NULL if it is not. |
| NULLABLE | Contains YES if the column may contain NULL values and '' if not. |
| INDEX_TYPE | The index method used (BTREE, FULLTEXT, HASH, RTREE). |
| COMMENT | Information about the index not described in its own column, such as disabled if the index is disabled. |
| INDEX_COMMENT | Any comment provided for the index with a COMMENT attribute when the index was created. |