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SHOW STATS_BUCKETS

SHOW STATS_BUCKETS 语句显示常规统计信息中桶的信息。

目前,SHOW STATS_BUCKETS 语句返回以下列:

列名说明
Db_name数据库名
Table_name表名
Partition_name分区名
Column_name取决于 Is_index 值:Is_index0 时显示列名,为 1 时显示索引名
Is_index是否是索引列
Bucket_id桶的 ID
Count该桶和之前桶中所有数值的个数
Repeats最大值的出现次数
Lower_bound最小值
Upper_bound最大值
Ndv桶中不同值的数量。该字段已废弃,其值由于不准确会始终显示为 0

语法图

ShowStatsBucketsStmt
SHOW STATS_BUCKETS ShowLikeOrWhere
ShowLikeOrWhere
LIKE SimpleExpr WHERE Expression

示例

SHOW STATS_BUCKETS WHERE Table_name='t';
+---------+------------+----------------+-------------+----------+-----------+-------+---------+--------------------------+--------------------------+------+
| Db_name | Table_name | Partition_name | Column_name | Is_index | Bucket_id | Count | Repeats | Lower_Bound              | Upper_Bound              | Ndv  |
+---------+------------+----------------+-------------+----------+-----------+-------+---------+--------------------------+--------------------------+------+
| test    | t          |                | a           |        0 |         0 |     1 |       1 | 2023-12-27 00:00:00      | 2023-12-27 00:00:00      |    0 |
| test    | t          |                | a           |        0 |         1 |     2 |       1 | 2023-12-28 00:00:00      | 2023-12-28 00:00:00      |    0 |
| test    | t          |                | ia          |        1 |         0 |     1 |       1 | (NULL, 2)                | (NULL, 2)                |    0 |
| test    | t          |                | ia          |        1 |         1 |     2 |       1 | (NULL, 4)                | (NULL, 4)                |    0 |
| test    | t          |                | ia          |        1 |         2 |     3 |       1 | (2023-12-27 00:00:00, 1) | (2023-12-27 00:00:00, 1) |    0 |
| test    | t          |                | ia          |        1 |         3 |     4 |       1 | (2023-12-28 00:00:00, 3) | (2023-12-28 00:00:00, 3) |    0 |
+---------+------------+----------------+-------------+----------+-----------+-------+---------+--------------------------+--------------------------+------+
6 rows in set (0.00 sec)

MySQL 兼容性

该语句是 TiDB 对 MySQL 语法的扩展。

另请参阅