Stuff (function)

使用字符串替换从指定位置开始指定长度的字符，返回新字符串

• Type: FUNCTION
• Returns: varchar(8000)
• Deterministic: NO
• SQL data access: CONTAINS SQL

Parameters

#	Mode	Name	Type
1	IN	str	varchar(8000)
2	IN	startIndex	int
3	IN	length	int
4	IN	Newstr	varchar(8000)

Body

Body is not pre-cached. To inspect: mysql --defaults-file=~/.my.cnf -e 'SHOW CREATE FUNCTIONStuff'.

Narrative

Business context: 使用字符串替换从指定位置开始指定长度的字符，返回新字符串 — SQL-Server STUFF polyfill. Removes a length-character window starting at startIndex from str and splices Newstr in its place. Used by the formula-replacement engine to substitute placeholders inside cost-formula strings at known offsets.

What it does: returns CONCAT(LEFT(str, startIndex-1), Newstr, RIGHT(str, ...)). The right-hand slice uses LOCATE(SUBSTR(str, startIndex, length), str) instead of the simpler startIndex + length, so when the deleted substring also occurs earlier in str the function would slice from the earlier occurrence (subtle bug — only safe when the substring is unique or the first occurrence is exactly at startIndex).

Invocation: referenced by the auto-send-check-message + formula-replace family: Sp_System_AutoSendCheckMsg, Sp_System_ReplaceField, Sp_System_ReplaceFieldNew, Sp_System_ReplaceField_Detail, Sp_System_ReplaceField_NEW, Sp_System_ReplaceField_NEW_ACT. Also referenced in xly-src upgrade scripts under script/标版/upgrade/20220111公式解析实际详情/ and 20220321计算获取公式解析/. No form-master binding — strictly an internal string helper.