Warning: file_get_contents(/data/phpspider/zhask/data//catemap/8/sorting/2.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
如何确保表实体中的值不会在mysql中重复?_Mysql - Fatal编程技术网

如何确保表实体中的值不会在mysql中重复?

如何确保表实体中的值不会在mysql中重复?,mysql,Mysql,在下表中,我希望属性_id是唯一的,这样它就不会有重复的值。这个的语法是什么 CREATE TABLE IF NOT EXISTS `propFeatures` ( `id` bigint(20) NOT NULL auto_increment, `bedroom` int(10) NOT NULL, `bathroom` int(10) NOT NULL, `balcony` int(10) NOT NULL, `furnished` tinyint(1) NOT NULL, `propert

在下表中,我希望属性_id是唯一的,这样它就不会有重复的值。这个的语法是什么

CREATE TABLE IF NOT EXISTS `propFeatures` (
`id` bigint(20) NOT NULL auto_increment,
`bedroom` int(10) NOT NULL,
`bathroom` int(10) NOT NULL,
`balcony` int(10) NOT NULL,
`furnished` tinyint(1) NOT NULL,
`property_id` int(10) NOT NULL,
PRIMARY KEY  (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8; 

您可以将
UNIQUE
约束添加到
property\u id
列中,以便在需要时不允许重复


要检查重复项,可以运行以下查询:

select property_id, count(property_id) as total from propFeatures
       group by property_id having count(property_id) > 1
如果要删除重复项,请查看此帖子以了解更多信息:


您可以在
属性id
列中添加
唯一的
约束,以便在需要时不允许重复


要检查重复项,可以运行以下查询:

select property_id, count(property_id) as total from propFeatures
       group by property_id having count(property_id) > 1
如果要删除重复项,请查看此帖子以了解更多信息: