MySQL SELECT 语句用于字段的“长度”大于 1
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MySQL SELECT statement for the "length" of the field is greater than 1
提问by TIMEX
I have an LINK field in my table. Some rows have a link, some don't.
我的表中有一个 LINK 字段。有些行有链接，有些没有。
I'd like to select all rows where LINK is present. (length is greater than X characters).
我想选择存在 LINK 的所有行。（长度大于 X 个字符）。
How do I write this?
我该怎么写？
回答by Jon Skeet
How about:
怎么样：
SELECT * FROM sometable WHERE CHAR_LENGTH(LINK) > 1
Here's the MySql string functions page(5.0).
这是MySql 字符串函数页面(5.0)。
Note that I chose CHAR_LENGTHinstead of LENGTH, as if there are multibyte characters in the data you're probably reallyinterested in how many characters there are, not how many bytes of storage they take. So for the above, a row where LINK is a single two-byte character wouldn't be returned - whereas it would when using LENGTH.
请注意，我选择了CHAR_LENGTH而不是LENGTH，好像数据中有多字节字符一样，您可能真正感兴趣的是有多少字符，而不是它们占用多少字节的存储空间。因此，对于上述情况，不会返回 LINK 是单个两字节字符的行 - 而使用LENGTH.
Note that if LINKis NULL, the result of CHAR_LENGTH(LINK)will be NULLas well, so the row won't match.
注意，如果LINK是NULL，结果CHAR_LENGTH(LINK)将是NULL一样，所以该行不匹配。
回答by Amy
select * from [tbl] where [link] is not null and len([link]) > 1
For MySQL user:
对于 MySQL 用户：
LENGTH([link]) > 1
回答by alizelzele
Just in case anybody want to find how in oracle and came here (like me), the syntax is
以防万一有人想在 oracle 中找到方法并来到这里（像我一样），语法是
select length(FIELD) from TABLE
just in case ;)
以防万一 ;）
回答by KM.
Try:
尝试：
SELECT
*
FROM
YourTable
WHERE
CHAR_LENGTH(Link) > x
