MySQL 从搜索问题开始
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MySQL starts with searching issue
提问by Jamie Hartnoll
I'm having an issue using the %wildcard with a MySQL query.
我在%MySQL 查询中使用通配符时遇到问题。
http://www.w3schools.com/sql/sql_like.asp
http://www.w3schools.com/sql/sql_like.asp
Having read that article, I am using %and not getting quite what I was expecting.
读过那篇文章后，我正在使用%并且没有得到我所期望的。
I have a series of values, such as
我有一系列的价值观，比如
1_1
1_2
2_1
2_2... etc
including
包含
11_1
11_2
Now, in some cases I want to return specifically those whose value = 11_2, or 1_2etc. This works fine
现在，在某些情况下，我想特别返回那些值= 11_2，或1_2等这工作正常
WHERE fieldName = '11_2'
etc... as expected
等等......正如预期的那样
However, in some cases I want to find all items which start with a 1or all items which start with 11
但是，在某些情况下，我想查找以 a 开头的1所有项目或所有以11
From the w3Schools link, I was expecting
从 w3Schools 链接，我期待
WHERE fieldName LIKE '1_%'
To find anything that begins with 1_specifically, therefore, in my example, returning:
要找到任何以1_特定开头的内容，因此，在我的示例中，返回：
1_1
1_2
BUT, it also returns
但是，它也返回
11_1
11_2
Why is this? And how can I over come it?
为什么是这样？我怎么能克服呢？
回答by markblandford
Underscore is a wildcard for a single character. You will need to change your SQL to something like:
下划线是单个字符的通配符。您需要将 SQL 更改为以下内容：
WHERE fieldName LIKE '1%'
Or you can escape the underscore
或者你可以转义下划线
WHERE fieldName LIKE '1\_%'
