統計_ヒストグラムを表示

このステートメントは、 ANALYZEステートメントによって収集されたヒストグラム情報を表示します。

あらすじ

ShowStmt

ShowStmt

ShowTargetFiltertable

ShowTargetFilterable

ShowLikeOrWhereOpt

ShowLikeOrWhereOpt

show stats_histograms;
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+
| Db_name | Table_name | Partition_name | Column_name | Is_index | Update_time         | Distinct_count | Null_count | Avg_col_size | Correlation |
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+
| test    | t          |                | a           |        0 | 2020-05-25 19:20:00 |              7 |          0 |            1 |           1 |
| test    | t2         |                | a           |        0 | 2020-05-25 19:20:01 |              6 |          0 |            8 |           0 |
| test    | t2         |                | b           |        0 | 2020-05-25 19:20:01 |              6 |          0 |         1.67 |           1 |
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+
3 rows in set (0.00 sec)
show stats_histograms where table_name = 't2';
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+
| Db_name | Table_name | Partition_name | Column_name | Is_index | Update_time         | Distinct_count | Null_count | Avg_col_size | Correlation |
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+
| test    | t2         |                | b           |        0 | 2020-05-25 19:20:01 |              6 |          0 |         1.67 |           1 |
| test    | t2         |                | a           |        0 | 2020-05-25 19:20:01 |              6 |          0 |            8 |           0 |
+---------+------------+----------------+-------------+----------+---------------------+----------------+------------+--------------+-------------+
2 rows in set (0.00 sec)

MySQL の互換性

このステートメントは、MySQL 構文に対する TiDB 拡張です。

こちらもご覧ください

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