如何计算 Oracle varchar 值中某个字符出现的次数?
如何计算 varchar2 字符串中字符 - 的出现次数?
How can I count number of occurrences of the character - in a varchar2 string?
示例:
select XXX('123-345-566', '-') from dual;
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2
推荐答案
给你:
select length('123-345-566') - length(replace('123-345-566','-',null))
from dual;
从技术上讲，如果你要检查的字符串只包含你要计数的字符，上面的查询将返回NULL；以下查询将在所有情况下给出正确答案:
Technically, if the string you want to check contains only the character you want to count, the above query will return NULL; the following query will give the correct answer in all cases:
select coalesce(length('123-345-566') - length(replace('123-345-566','-',null)), length('123-345-566'), 0)
from dual;
coalesce 中的最后一个 0 捕捉您在空字符串中计数的情况(即 NULL，因为在 ORACLE 中 length(NULL) = NULL).
The final 0 in coalesce catches the case where you're counting in an empty string (i.e. NULL, because length(NULL) = NULL in ORACLE).
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