SHOW STATS_HISTOGRAMS

你可以使用 SHOW STATS_HISTOGRAMS 语句查看通过 ANALYZE 语句 收集的直方图信息,该内容是数据库常规统计信息 的一部分。

语法图

ShowStatsHistogramsStmt
SHOWSTATS_HISTOGRAMSShowLikeOrWhere
ShowLikeOrWhere
LIKESimpleExprWHEREExpression

示例

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 兼容性

该语句是 TiDB 对 MySQL 语法的扩展。

另请参阅

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