MySQL mysql查询中<>是什么意思？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/39075213/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
What is the meaning of <> in mysql query?
提问by Manoj venk
I have a MySQL query that includes <> in it. I don't know the exact usage of it.
我有一个包含 <> 的 MySQL 查询。我不知道它的确切用法。
SELECT * FROM table_laef WHERE id = ? AND genre_type <> 'LIVE'
P.S.: Im sorry for this basic syntax, since I have searched for this on Google. All they give is about <=>. Thanks anyway, guys!
PS：我很抱歉这个基本语法，因为我在谷歌上搜索过这个。他们所提供的只是关于<=>。无论如何，谢谢，伙计们！
回答by Reece Kenney
回答by Raman Sahasi
回答by Bear Nithi
<>means NOT EQUAL TO, !=also means NOT EQUAL TO. It's just another syntactic sugar. both <>and !=are same.
<>意味着不等于，!=也意味着不等于。这只是另一种语法糖。这两个<>和!=是一样的。
The below two examples are doing the same thing. Query publisher table to bring results which are NOT EQUAL TO <> !=USA.
下面的两个例子正在做同样的事情。查询发布者表以带来不等于<> !=美国的结果。
SELECT pub_name,country,pub_city,estd FROM publisher WHERE country <> "USA";
SELECT pub_name,country,pub_city,estd FROM publisher WHERE country <> "USA";
SELECT pub_name,country,pub_city,estd FROM publisher WHERE country != "USA";
SELECT pub_name,country,pub_city,estd FROM publisher WHERE country != "USA";
回答by user1751658
In MySQL, I use <>to preferentially place specific rows at the front of a sort request.
在 MySQL 中，我使用<>优先将特定行放在排序请求的前面。
For instance, under the column topic, I have the classifications of 'Chair', 'Metabolomics', 'Proteomics', and 'Endocrine'. I always want to list any individual(s) with the topic 'Chair', first, and then list the other members in alphabetical order based on their topicand then their name_last.
例如，在列下topic，我有“椅子”、“代谢组学”、“蛋白质组学”和“内分泌”的分类。我总是想首先列出主题为“主席”的任何个人，然后根据他们的字母顺序列出其他成员topic，然后是他们的name_last.
I do this with:
我这样做：
SELECT scicom_list ORDER BY topic <> 'Chair',topic,name_last;
This outputs the rows in the order of:
Chair
Endocrine
Metabolomics
Proteomics
这将按以下顺序输出行：
Chair
Endocrine
Metabolomics
Proteomics
Notice that topic <> 'Chair'is used to select all the rows with 'Chair' first. It then sorts the rows where topic = Chairby name_last.*
请注意，topic <> 'Chair'它用于首先选择带有“椅子”的所有行。然后topic = Chair按name_last.*对行进行排序
*This is a bit counterintuitive since <>equals !=based on other feedback in this post.
*这有点违反直觉，因为<>等于!=基于本文中的其他反馈。
This syntax can also be used to prioritize multiple categories. For instance, if I want to have "Chair" and then "Vice Chair" listed before the rest of the topics, I use the following
此语法还可用于确定多个类别的优先级。例如，如果我想在其余主题之前列出“主席”和“副主席”，我使用以下
SELECT scicom_list ORDER BY topic <> 'Chair',topic <> 'Vice Chair',topic,name_last;
This outputs the rows in the order of:
Chair
Vice Chair
Endocrine
Metabolomics
Proteomics
这将按以下顺序输出行：
主席
副主席
内分泌
代谢
组学蛋白质组学
回答by Arun Kumar N
<>is equal to !=i.e, both are used to represent the NOT EQUAL operation. For instance, email <> ''and email != ''are same.
<>等于!=即，两者都用于表示 NOT EQUAL 运算。例如，email <> ''和email != ''是一样的。
