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title: SHOW STATS_BUCKETS | ||
summary: TiDB 数据库中 SHOW STATS_BUCKETS 的使用概况。 | ||
--- | ||
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# SHOW STATS_BUCKETS | ||
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`SHOW STATS_BUCKETS` 语句显示[常规统计信息](/statistics.md)中桶的信息。 | ||
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目前,`SHOW STATS_BUCKETS` 语句返回以下列: | ||
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| 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_index` 为 `0` 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`。 | | ||
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## 语法图 | ||
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```ebnf+diagram | ||
ShowStatsBucketsStmt ::= | ||
"SHOW" "STATS_BUCKETS" ShowLikeOrWhere? | ||
ShowLikeOrWhere ::= | ||
"LIKE" SimpleExpr | ||
| "WHERE" Expression | ||
``` | ||
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## 示例 | ||
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```sql | ||
SHOW STATS_BUCKETS WHERE Table_name='t'; | ||
``` | ||
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``` | ||
+---------+------------+----------------+-------------+----------+-----------+-------+---------+--------------------------+--------------------------+------+ | ||
| 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) | ||
``` | ||
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## MySQL 兼容性 | ||
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该语句是 TiDB 对 MySQL 语法的扩展。 | ||
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## 另请参阅 | ||
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* [`ANALYZE`](/sql-statements/sql-statement-analyze-table.md) | ||
* [常规统计信息](/statistics.md) |
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