MySQL利用procedure analyse()函數優化表結構

簡介

procedure analyse()函數是MySQL內置的對MySQL字段值進行統計分析後給出建議的字段類型。

語法

procesure analyse(max_elements,max_memory)

max_elements

指定每列非重復值的最大值，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復值所采用的最大內存大小。

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

以上就是關於MySQL中procedure analyse()函數的全部內容了，希望本文的內容對大家的學習或者工作能帶來一定的幫助，如果有疑問大家可以留言交流。