Note
This view is available starting with V3.2.1.
Purpose
This view displays the column statistics and histogram information of tables owned by the current user.
Applicability
This view is available only in Oracle mode.
Columns
Column |
Type |
Nullable |
Description |
|---|---|---|---|
| TABLE_NAME | VARCHAR2(128) | NO | The name of the table to which the column belongs. |
| COLUMN_NAME | VARCHAR2(128) | NO | The name of the column. |
| NUM_DISTINCT | NUMBER | YES | The number of distinct values in the column. |
| LOW_VALUE | VARCHAR2(128) | YES | The minimum value of the column. |
| HIGH_VALUE | VARCHAR2(128) | YES | The maximum value of the column. |
| DENSITY | NUMBER | YES | The density of the column. |
| NUM_NULLS | NUMBER | YES | The number of NULL values in the column. |
| NUM_BUCKETS | NUMBER | YES | The number of buckets in the histogram of the column. |
| LAST_ANALYZED | DATE | YES | The time when the last analysis was performed. |
| SAMPLE_SIZE | NUMBER | YES | The sampling size during the analysis. |
| GLOBAL_STATS | VARCHAR2(3) | YES |
|
| USER_STATS | VARCHAR2(3) | YES | Indicates whether the partition statistics are user-defined. |
| NOTES | VARCHAR2(80) | YES | Records some additional attributes. |
| AVG_COL_LEN | NUMBER | YES | The average length of the column. |
| HISTOGRAM | VARCHAR2(15) | YES | The histogram type. |
| SCOPE | VARCHAR2(7) | YES | The scope of the statistics. |
Sample query
Query the column statistics and histogram information of the T_SUBPART table owned by the current user.
obclient [SYS]> SELECT TABLE_NAME, COLUMN_NAME, NUM_DISTINCT, LOW_VALUE, HIGH_VALUE, DENSITY, NUM_NULLS, NUM_BUCKETS, SAMPLE_SIZE, AVG_COL_LEN, HISTOGRAM FROM SYS.USER_TAB_COL_STATISTICS WHERE TABLE_NAME ='T_SUBPART' ORDER BY 1, 2, 3;
The query result is as follows:
+------------+-------------+--------------+-----------+------------+------------------------+-----------+-------------+-------------+-------------+-----------+
| TABLE_NAME | COLUMN_NAME | NUM_DISTINCT | LOW_VALUE | HIGH_VALUE | DENSITY | NUM_NULLS | NUM_BUCKETS | SAMPLE_SIZE | AVG_COL_LEN | HISTOGRAM |
+------------+-------------+--------------+-----------+------------+------------------------+-----------+-------------+-------------+-------------+-----------+
| T_SUBPART | C1 | 10191 | 0 | 9999 | .000098125797272102829 | 0 | 5 | 10000 | 20 | HYBRID |
| T_SUBPART | C2 | 1031 | 0 | 999 | .00096993210475266732 | 0 | 5 | 10000 | 20 | HYBRID |
| T_SUBPART | C3 | 1973 | 0 | 1999 | .00050684237202230106 | 0 | 5 | 10000 | 20 | HYBRID |
+------------+-------------+--------------+-----------+------------+------------------------+-----------+-------------+-------------+-------------+-----------+
3 rows in set
References
View the statistics of tables accessible to the current user: ALL_TAB_COL_STATISTICS
View the statistics of all tables in the current tenant: DBA_TAB_COL_STATISTICS
To query column statistics at the table level, query the following views:
To query column statistics at the partition level, query the following views:
To query column statistics at the subpartition level, query the following views:
To query histogram statistics at the table level, query the following views:
To query histogram statistics at the partition level, query the following views:
To query histogram statistics at the subpartition level, query the following views:
To query index statistics, query the following views:
For information about how to collect statistics, see the following topics: