docs: fix sum() in en/25-application/_03-immigrate.md

docs/en/25-application/_03-immigrate.md

@@ -338,7 +338,7 @@ Remark:
 Equivalent function: sum
 
 ```sql
-Select max(value) from (select first(val) value from table_name interval(10s) fill(linear)) interval(10s)
+Select sum(value) from (select first(val) value from table_name interval(10s) fill(linear)) interval(10s)
 ```
 
 Note: This function has no interpolation requirements, so it can be directly calculated.

docs/zh/25-application/03-immigrate.md

@@ -371,7 +371,7 @@ Select min(val) from table_name
 等效函数：sum
 
 ```sql
-Select max(value) from (select first(val) value from table_name interval(10s) fill(linear)) interval(10s)
+Select sum(value) from (select first(val) value from table_name interval(10s) fill(linear)) interval(10s)
 ```
 
 备注：该函数无插值需求，因此可用直接计算。