Oracle length() 函数返回错误值
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Oracle length() function returning incorrect value
提问by Andreas Wong
I just found some... I don't know what I'd call it but here goes:
我刚刚找到了一些......我不知道我会怎么称呼它，但这里是：
SELECT part_num,
length(trim(part_num))
FROM part_programs
WHERE rownum <= 10;
...results:
...结果：
PART_NUM LENGTH(TRIM(PART_NUM))
--------------- ----------------------
THAB256 8
THA1256674 11
THA1256674GU 13
THA1257141 11
THA1257141FR 13
THA1257141FR1 14
THA1257141TD 13
THA2002013 11
THA2002013MI 13
THA2002013MI1 14
The returned integer from length() call actually returns 1 + realLength of the values.
length() 调用返回的整数实际上返回值的 1 + realLength。
I'm not sure where to begin, anyone care to shed a light?
我不知道从哪里开始，有人愿意透露一下吗？
回答by PaulJ
Try looking at the detail of the field by using the built in DUMP function
尝试使用内置的 DUMP 函数查看字段的详细信息
SELECT part_num,
length(trim(part_num)),
dump( trim( part_num ) )
FROM part_programs
WHERE rownum <= 10;
This will return data like
这将返回类似的数据
Typ=96 Len=6: 79,114,97,99,108,101
from this query
从这个查询
SELECT dump( 'Oracle' ) from dual
回答by Ron Savage
You probably have a non-visible character (like a CR) on the end of those part_nums that TRIM() does not remove.
在 TRIM() 不会删除的那些 part_nums 的末尾，您可能有一个不可见的字符（如 CR）。
Just a guess. :-)
只是一个猜测。:-)
Try bracketing them with '[' || part_num || ']' in the select and see if you notice some extra white-space on either side of the field.
尝试用 '[' || 将它们括起来 part_num || ']' 在选择中，看看您是否注意到字段两侧有一些额外的空白。
