MySQL利用procedure analyse()函數最佳化表結構_Mysql

簡介

procedure analyse()函數是MySQL內建的對MySQL欄位值進行統計分析後給出建議的欄位類型。

文法

procesure analyse(max_elements,max_memory)

max_elements

指定每列非重複值的最大值，當超過這個值的時候，MySQL不會推薦enum類型。

max_memory

analyse()為每列找出所有非重複值所採用的最大記憶體大小。

實戰演練

# 對t1表所有的列進行分析wing@3306>show create table t1;+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------+| Table | Create Table                                                                      |+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------+| t1  | CREATE TABLE `t1` ( `id` int(11) DEFAULT NULL, `name` varchar(16) DEFAULT NULL, `score` int(11) DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=utf8 |+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------+1 row in set (0.00 sec)wing@3306>select * from t1 procedure analyse(4);+---------------+-----------+-----------+------------+------------+------------------+-------+-------------------------+-------------+--------------------------------+| Field_name  | Min_value | Max_value | Min_length | Max_length | Empties_or_zeros | Nulls | Avg_value_or_avg_length | Std     | Optimal_fieldtype       |+---------------+-----------+-----------+------------+------------+------------------+-------+-------------------------+-------------+--------------------------------+| wing.t1.id  | 1     | 200000  |     1 |     6 |        0 |   0 | 100000.5000       | 116099.2790 | MEDIUMINT(6) UNSIGNED NOT NULL || wing.t1.name | 000jxc6V | zzznmkcX |     8 |     8 |        0 |   0 | 8.0000         | NULL    | CHAR(8) NOT NULL        || wing.t1.score | 1     | 100    |     1 |     3 |        0 |   0 | 50.4889         | 28.8768   | TINYINT(3) UNSIGNED NOT NULL  |+---------------+-----------+-----------+------------+------------+------------------+-------+-------------------------+-------------+--------------------------------+3 rows in set (0.14 sec)

總結

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