簡(jiǎn)介
procedure analyse()函數(shù)是MySQL內(nèi)置的對(duì)MySQL字段值進(jìn)行統(tǒng)計(jì)分析后給出建議的字段類型。
語(yǔ)法
procesure analyse(max_elements,max_memory)
max_elements
指定每列非重復(fù)值的最大值，當(dāng)超過這個(gè)值的時(shí)候，MySQL不會(huì)推薦enum類型。
max_memory
analyse()為每列找出所有非重復(fù)值所采用的最大內(nèi)存大小。
實(shí)戰(zhàn)演練
# 對(duì)t1表所有的列進(jìn)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(jié)
以上就是關(guān)于MySQL中procedure analyse()函數(shù)的全部?jī)?nèi)容了，希望本文的內(nèi)容對(duì)大家的學(xué)習(xí)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。
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