如何使用sql字符索引在单词Malayalam.com中找到第三个“a”位置？

您可以使用：

CHARINDEX ( expressionToFind , expressionToSearch [ , start_location ] )

您可以使用：

CHARINDEX ( expressionToFind , expressionToSearch [ , start_location ] )

---

我想你在找我

WITH cte AS (
  SELECT 'Malayalam' s
)
SELECT cte.s, s3.r
FROM cte
OUTER APPLY (SELECT CHARINDEX('a', cte.s, 0))      s1(r) -- first occurence
OUTER APPLY (SELECT CHARINDEX('a', cte.s, s1.r+1)) s2(r) -- second occurence
OUTER APPLY (SELECT CHARINDEX('a', cte.s, s2.r+1)) s3(r) -- third occurence
-- ...

---

我想你在找我

WITH cte AS (
  SELECT 'Malayalam' s
)
SELECT cte.s, s3.r
FROM cte
OUTER APPLY (SELECT CHARINDEX('a', cte.s, 0))      s1(r) -- first occurence
OUTER APPLY (SELECT CHARINDEX('a', cte.s, s1.r+1)) s2(r) -- second occurence
OUTER APPLY (SELECT CHARINDEX('a', cte.s, s2.r+1)) s3(r) -- third occurence
-- ...

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还可以使用CHARINDEX获取字符“a”的第三个位置，如下所示-

仅当存在至少3个字符“a”时，才会返回正确的结果

+----------------------+-----------+-----------+
| CharPositionInString | Character | Occurence |
+----------------------+-----------+-----------+
|                    1 | M         |         1 |
|                    2 | a         |         1 |
|                    3 | l         |         1 |
|                    4 | a         |         2 |
|                    5 | y         |         1 |
|                    6 | a         |         3 |
|                    7 | l         |         2 |
|                    8 | a         |         4 |
|                    9 | m         |         2 |
+----------------------+-----------+-----------+

---

还可以使用CHARINDEX获取字符“a”的第三个位置，如下所示-

仅当存在至少3个字符“a”时，才会返回正确的结果

+----------------------+-----------+-----------+
| CharPositionInString | Character | Occurence |
+----------------------+-----------+-----------+
|                    1 | M         |         1 |
|                    2 | a         |         1 |
|                    3 | l         |         1 |
|                    4 | a         |         2 |
|                    5 | y         |         1 |
|                    6 | a         |         3 |
|                    7 | l         |         2 |
|                    8 | a         |         4 |
|                    9 | m         |         2 |
+----------------------+-----------+-----------+

---

你到底想干什么？为什么要用CHARINDEX？你到底想做什么？为什么要使用CHARINDEX？