MySQL 区分大小写的查询
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MySQL case sensitive query
提问by Michael Liao
This has been asked on this site before but I couldn't find a sufficient answer. If I'm doing a query like:
以前在这个网站上有人问过这个问题，但我找不到足够的答案。如果我正在做这样的查询：
Select Seller from Table where Location = 'San Jose'
How can I make it return only Sellers with Location 'San Jose' instead of 'san jose' or something else?
我怎样才能让它只返回位置为“圣何塞”而不是“圣何塞”或其他东西的卖家？
回答by James mason
MySQL queries are not case-sensitive by default. Following is a simple query that is looking for 'value'. However it will return 'VALUE', 'value', 'VaLuE', etc…
默认情况下，MySQL 查询不区分大小写。以下是一个寻找“值”的简单查询。但是它会返回“VALUE”、“value”、“Value”等……
SELECT * FROM `table` WHERE `column` = 'value'
The good news is that if you need to make a case-sensitive query, it is very easy to do using the BINARYoperator, which forces a byte by byte comparison:
好消息是，如果您需要进行区分大小写的查询，使用BINARY运算符非常容易，它会强制逐字节比较：
SELECT * FROM `table` WHERE BINARY `column` = 'value'
回答by Shenxian
To improve James' excellent answer:
为了改进詹姆斯的出色回答：
It's better to put BINARYin front of the constant instead:
最好放在BINARY常量前面：
SELECT * FROM `table` WHERE `column` = BINARY 'value'
Putting BINARYin front of columnwill prevent the use of any index on that column.
放在BINARY前面column将阻止在该列上使用任何索引。
回答by Thomas Clowes
Whilst the listed answer is correct, may I suggest that if your column is to hold case sensitive strings you read the documentationand alter your table definition accordingly.
虽然列出的答案是正确的，但我可以建议，如果您的列要保存区分大小写的字符串，请阅读文档并相应地更改表定义。
In my case this amounted to defining my column as:
就我而言，这相当于将我的专栏定义为：
`tag` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT ''
This is in my opinion preferential to adjusting your queries.
我认为这优先于调整您的查询。
