如何在 MySQL 中的 instr() 中使用区分大小写？

发布于 2024-08-17 04:58:25 字数 730 浏览 7 评论 0原文

可能的重复链接显示了一个与我当前的查询完全相同的查询。但是，我找不到一种方法使其成为敏感匹配。 :\

SELECT COUNT(*) FROM users WHERE INSTR(flags, 'T') > 0;

我得到的计数是 46，这显然是错误的。它计算标志中的每个实例“T”，无论它是大写还是小写。

它按照 MySQL 文档工作。我在 MySQL 文档中发现一些内容，说要在变量上放置“@”符号以使其区分大小写匹配。但是，我在 @'T' 上尝试了此操作以形成以下查询：

SELECT COUNT(*) FROM users WHERE INSTR(flags, @'T') > 0;

我得到的计数为零。

有人能为我解释一下吗？ :)

编辑：

忘记提及，抱歉。我还尝试了 LIKE '%T%' 作为 where 子句，但仍然失败并返回与 (INSTR(flags, 'T') > 0);

原文

Possible duplicate: How to apply wildcard in instr() in MySQL?

The possible duplicate linked shows a query which is exactly like my current one sort of. However, I cannot find a way to make it a case sensitive match. :\

SELECT COUNT(*) FROM users WHERE INSTR(flags, 'T') > 0;

I get a count of 46 which is obviously wrong. It's counting every instance "T" in flags whether it's upper- or lower-case.

It works as according to the MySQL documentation. I found something in the MySQL docs that said to put an "@" symbol on a variable to make it a case sensitive match. However, I tried this on the @'T' to form the following query:

SELECT COUNT(*) FROM users WHERE INSTR(flags, @'T') > 0;

I get a count of zero.

Could anyone shed some light on this for me? :)

EDIT:

Forgot to mention, sorry. I also tried a LIKE '%T%' as the where-clause, which still failed and returns the same as (INSTR(flags, 'T') > 0);

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

泅渡 2024-08-24 04:58:25

我相信这会起作用

SELECT COUNT(*) FROM users WHERE INSTR(binary flags, 'T') > 0;

I believe this will work

SELECT COUNT(*) FROM users WHERE INSTR(binary flags, 'T') > 0;

回复收藏 0 原文

硬不硬你别怂 2024-08-24 04:58:25

经测试，

SELECT binary 'AKkRBbagSsPpCtmxeGhUX' LIKE '%T%';

按预期生成“0”。根据字符串比较文档，LIKE如果其中一个操作数是二进制的，则执行二进制（因此区分大小写）比较。

Tested,

SELECT binary 'AKkRBbagSsPpCtmxeGhUX' LIKE '%T%';

produces '0', as expected. According to the String Comparison documentation, LIKE performs a binary (thus, case-sensitive) comparison if either of its operands are binary.

回复收藏 0 原文

~没有更多了~