add doc for sum_int

functions-and-operators/aggregate-group-by-functions.md

@@ -33,6 +33,53 @@ This section describes the supported MySQL `GROUP BY` aggregate functions in TiD
 
 In addition, TiDB also provides the following aggregate functions:
 
++ `SUM_INT(expr)`
+
+    This function returns the sum of the integer expression `expr`. It works similarly to `SUM(expr)`, but only accepts integer arguments, including `TINYINT`, `SMALLINT`, `MEDIUMINT`, `INT`, and `BIGINT`. For a signed integer argument, the return type is `BIGINT`. For an unsigned integer argument, the return type is `BIGINT UNSIGNED`. If the sum of non-`NULL` values exceeds the range of the return type, TiDB returns an integer overflow error.
+
+    `SUM_INT()` ignores `NULL` values by default. If there are no non-`NULL` values, it returns `NULL`. `SUM_INT()` supports `DISTINCT` and can be used as a [window function](/functions-and-operators/window-functions.md).
+
+    The following example shows how to use this function:
+
+    ```sql
+    DROP TABLE IF EXISTS t;
+    CREATE TABLE t(id INT PRIMARY KEY, a BIGINT, b BIGINT UNSIGNED);
+    INSERT INTO t VALUES(1, 1, 1), (2, 1, 1), (3, 2, 2), (4, NULL, NULL);
+    ```
+
+    ```sql
+    SELECT SUM_INT(a), SUM_INT(DISTINCT a), SUM_INT(b) FROM t;
+    ```
+
+    ```sql
+    +------------+---------------------+------------+
+    | SUM_INT(a) | SUM_INT(DISTINCT a) | SUM_INT(b) |
+    +------------+---------------------+------------+
+    |          4 |                   3 |          4 |
+    +------------+---------------------+------------+
+    1 row in set (0.00 sec)
+    ```
+
+    The following example uses `SUM_INT()` as a window function:
+
+    ```sql
+    SELECT id, a, SUM_INT(a) OVER (ORDER BY id ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS rolling_sum
+    FROM t
+    ORDER BY id;
+    ```
+
+    ```sql
+    +----+------+-------------+
+    | id | a    | rolling_sum |
+    +----+------+-------------+
+    |  1 |    1 |           1 |
+    |  2 |    1 |           2 |
+    |  3 |    2 |           3 |
+    |  4 | NULL |           2 |
+    +----+------+-------------+
+    4 rows in set (0.00 sec)
+    ```
+
 + `APPROX_PERCENTILE(expr, constant_integer_expr)`
 
     This function returns the percentile of `expr`. The `constant_integer_expr` argument indicates the percentage value which is a constant integer in the range of `[1,100]`. A percentile P<sub>k</sub> (`k` represents percentage) indicates that there are at least `k%` values in the data set that are less than or equal to P<sub>k</sub>.
@@ -86,7 +133,7 @@ In addition, TiDB also provides the following aggregate functions:
     2 rows in set (0.00 sec)
     ```
 
-Except for the `GROUP_CONCAT()`, `APPROX_PERCENTILE()`, and `APPROX_COUNT_DISTINCT` functions, all the preceding functions can serve as [Window functions](/functions-and-operators/window-functions.md).
+Except for the `GROUP_CONCAT()`, `APPROX_PERCENTILE()`, and `APPROX_COUNT_DISTINCT()` functions, all the preceding functions can serve as [window functions](/functions-and-operators/window-functions.md).
 
 ## GROUP BY modifiers
 

functions-and-operators/expressions-pushed-down.md

@@ -26,7 +26,7 @@ TiFlash also supports pushdown for the functions and operators [listed on this p
 | [JSON functions](/functions-and-operators/json-functions.md) | [JSON_ARRAY_APPEND()](/functions-and-operators/json-functions/json-functions-modify.md#json_array_append) <br/>[JSON_ARRAY()](/functions-and-operators/json-functions/json-functions-create.md#json_array) <br/>[JSON_CONTAINS()](/functions-and-operators/json-functions/json-functions-search.md#json_contains) <br/>[JSON_EXTRACT()](/functions-and-operators/json-functions/json-functions-search.md#json_extract) <br/>[JSON_INSERT()](/functions-and-operators/json-functions/json-functions-modify.md#json_insert) <br/>[JSON_LENGTH()](/functions-and-operators/json-functions/json-functions-return.md#json_length) <br/>[JSON_MERGE_PATCH()](/functions-and-operators/json-functions/json-functions-modify.md#json_merge_patch) <br/>[JSON_MERGE()](/functions-and-operators/json-functions/json-functions-modify.md#json_merge) <br/>[JSON_OBJECT()](/functions-and-operators/json-functions/json-functions-create.md#json_object) <br/>[JSON_REMOVE()](/functions-and-operators/json-functions/json-functions-modify.md#json_remove) <br/>[JSON_REPLACE()](/functions-and-operators/json-functions/json-functions-modify.md#json_replace) <br/>[JSON_SET()](/functions-and-operators/json-functions/json-functions-modify.md#json_set) <br/>[JSON_TYPE()](/functions-and-operators/json-functions/json-functions-return.md#json_type) <br/>[JSON_UNQUOTE()](/functions-and-operators/json-functions/json-functions-modify.md#json_unquote) <br/>[JSON_VALID()](/functions-and-operators/json-functions/json-functions-return.md#json_valid) <br/>[MEMBER OF()](/functions-and-operators/json-functions/json-functions-search.md#member-of) |
 | [Date and time functions](/functions-and-operators/date-and-time-functions.md) | [DATE()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_date) <br/>[DATE_FORMAT()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_date-format) <br/>[DATEDIFF()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_datediff) <br/>[DAYOFMONTH()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_dayofmonth) <br/>[DAYOFWEEK()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_dayofweek) <br/>[DAYOFYEAR()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_dayofyear) <br/>[FROM_DAYS()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_from-days) <br/>[HOUR()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_hour) <br/>[MAKEDATE()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_makedate) <br/>[MAKETIME()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_maketime) <br/>[MICROSECOND()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_microsecond) <br/>[MINUTE()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_minute) <br/>[MONTH()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_month) <br/>[MONTHNAME()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_monthname) <br/>[PERIOD_ADD()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_period-add) <br/>[PERIOD_DIFF()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_period-diff) <br/>[SEC_TO_TIME()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_sec-to-time) <br/>[SECOND()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_second) <br/>[SYSDATE()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_sysdate) <br/>[TIME_TO_SEC()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_time-to-sec) <br/>[TIMEDIFF()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_timediff) <br/>[WEEK()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_week) <br/>[WEEKOFYEAR()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_weekofyear) <br/>[YEAR()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_year) <br/>[DATE_ADD()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_date-add) <br/>[DATE_SUB()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_date-sub) <br/>[ADDDATE()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_adddate) <br/>[SUBDATE()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_subdate) <br/>[FROM_UNIXTIME()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_from-unixtime) <br/>[TIMESTAMPDIFF()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_timestampdiff) <br/>[UNIX_TIMESTAMP()](https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_unix-timestamp) |
 | [String functions](/functions-and-operators/string-functions.md) | [ASCII()](/functions-and-operators/string-functions.md#ascii) <br/>[BIT_LENGTH()](/functions-and-operators/string-functions.md#bit_length) <br/>[CHAR()](/functions-and-operators/string-functions.md#char) <br/>[CHAR_LENGTH()](/functions-and-operators/string-functions.md#char_length) <br/>[CONCAT()](/functions-and-operators/string-functions.md#concat) <br/>[CONCAT_WS()](/functions-and-operators/string-functions.md#concat_ws) <br/>[ELT()](/functions-and-operators/string-functions.md#elt) <br/>[FIELD()](/functions-and-operators/string-functions.md#field) <br/>[HEX()](/functions-and-operators/string-functions.md#hex) <br/>[LENGTH()](/functions-and-operators/string-functions.md#length) <br/>[LIKE](/functions-and-operators/string-functions.md#like) <br/>[LOWER()](/functions-and-operators/string-functions.md#lower) <br/>[LTRIM()](/functions-and-operators/string-functions.md#ltrim) <br/>[MID()](/functions-and-operators/string-functions.md#mid) <br/>[NOT LIKE](/functions-and-operators/string-functions.md#not-like) <br/>[NOT REGEXP](/functions-and-operators/string-functions.md#not-regexp) <br/>[REGEXP](/functions-and-operators/string-functions.md#regexp) <br/>[REGEXP_LIKE()](/functions-and-operators/string-functions.md#regexp_like) <br/>[REGEXP_REPLACE()](/functions-and-operators/string-functions.md#regexp_replace) <br/>[REGEXP_SUBSTR()](/functions-and-operators/string-functions.md#regexp_substr) <br/>[REPLACE()](/functions-and-operators/string-functions.md#replace) <br/>[REVERSE()](/functions-and-operators/string-functions.md#reverse) <br/>[RIGHT()](/functions-and-operators/string-functions.md#right), [RLIKE](/functions-and-operators/string-functions.md#rlike) <br/>[RTRIM()](/functions-and-operators/string-functions.md#rtrim) <br/>[SPACE()](/functions-and-operators/string-functions.md#space) <br/>[STRCMP()](/functions-and-operators/string-functions.md#strcmp) <br/>[SUBSTR()](/functions-and-operators/string-functions.md#substr) <br/>[SUBSTRING()](/functions-and-operators/string-functions.md#substring) <br/>[UPPER()](/functions-and-operators/string-functions.md#upper) |
-| [Aggregation functions](/functions-and-operators/aggregate-group-by-functions.md#aggregate-group-by-functions) | [COUNT()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_count) <br/>[COUNT(DISTINCT)](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_count-distinct) <br/>[SUM()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_sum) <br/>[AVG()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_avg) <br/>[MAX()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_max) <br/>[MIN()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_min) <br/>[VARIANCE()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_variance) <br/>[VAR_POP()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_var-pop) <br/>[STD()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_std) <br/>[STDDEV()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_stddev) <br/>[STDDEV_POP](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_stddev-pop) <br/>[VAR_SAMP()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_var-samp) <br/>[STDDEV_SAMP()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_stddev-samp) <br/>[JSON_ARRAYAGG(key)](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_json-arrayagg) <br/>[JSON_OBJECTAGG(key, value)](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_json-objectagg) |
+| [Aggregation functions](/functions-and-operators/aggregate-group-by-functions.md#aggregate-group-by-functions) | [COUNT()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_count) <br/>[COUNT(DISTINCT)](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_count-distinct) <br/>[SUM()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_sum) <br/>[`SUM_INT()`](/functions-and-operators/aggregate-group-by-functions.md) <br/>[AVG()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_avg) <br/>[MAX()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_max) <br/>[MIN()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_min) <br/>[VARIANCE()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_variance) <br/>[VAR_POP()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_var-pop) <br/>[STD()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_std) <br/>[STDDEV()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_stddev) <br/>[STDDEV_POP](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_stddev-pop) <br/>[VAR_SAMP()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_var-samp) <br/>[STDDEV_SAMP()](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_stddev-samp) <br/>[JSON_ARRAYAGG(key)](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_json-arrayagg) <br/>[JSON_OBJECTAGG(key, value)](https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_json-objectagg) |
 | [Encryption and compression functions](/functions-and-operators/encryption-and-compression-functions.md#encryption-and-compression-functions) | [MD5()](/functions-and-operators/encryption-and-compression-functions.md#md5) <br/>[SHA1(), SHA()](/functions-and-operators/encryption-and-compression-functions.md#sha1) <br/>[UNCOMPRESSED_LENGTH()](/functions-and-operators/encryption-and-compression-functions.md#uncompressed_length) |
 | [Cast functions and operators](/functions-and-operators/cast-functions-and-operators.md#cast-functions-and-operators) | [CAST()](/functions-and-operators/cast-functions-and-operators.md#cast) <br/>[CONVERT()](/functions-and-operators/cast-functions-and-operators.md#convert) |
 | [Miscellaneous functions](/functions-and-operators/miscellaneous-functions.md#supported-functions) | [UUID()](/functions-and-operators/miscellaneous-functions.md#uuid) |

functions-and-operators/window-functions.md

@@ -16,7 +16,7 @@ In TiDB, you can control window functions using the following system variables:
 
 The window functions [listed here](/tiflash/tiflash-supported-pushdown-calculations.md) can be pushed down to TiFlash.
 
-Except for `GROUP_CONCAT()` and `APPROX_PERCENTILE()`, TiDB supports using all [`GROUP BY` aggregate functions](/functions-and-operators/aggregate-group-by-functions.md) as window functions. In addition, TiDB supports the following window functions:
+Except for `GROUP_CONCAT()`, `APPROX_PERCENTILE()`, and `APPROX_COUNT_DISTINCT()`, TiDB supports using all [`GROUP BY` aggregate functions](/functions-and-operators/aggregate-group-by-functions.md) as window functions, including the TiDB-specific `SUM_INT()` function. In addition, TiDB supports the following window functions:
 
 | Function name                     | Feature description |
 | :-------------------------------- | :------------------------------------- |
@@ -474,4 +474,4 @@ FROM
 |   31 |                   11 |
 +------+----------------------+
 11 rows in set (0.00 sec)
-```
+```

tiflash/tiflash-supported-pushdown-calculations.md

@@ -44,7 +44,7 @@ TiFlash supports the following push-down expressions:
 | [JSON function](/functions-and-operators/json-functions.md) | `JSON_LENGTH()`, `->`, `->>`, `JSON_EXTRACT()`, `JSON_ARRAY()`, `JSON_DEPTH()`, `JSON_VALID()`, `JSON_KEYS()`, `JSON_CONTAINS_PATH()`, `JSON_UNQUOTE()` |
 | [Vector function](/ai/reference/vector-search-functions-and-operators.md) | `VEC_L2_DISTANCE`, `VEC_COSINE_DISTANCE`, `VEC_NEGATIVE_INNER_PRODUCT`, `VEC_L1_DISTANCE`, `VEC_DIMS`, `VEC_L2_NORM`, `VEC_AS_TEXT` |
 | [Conversion functions](/functions-and-operators/cast-functions-and-operators.md) | `CAST(int AS DOUBLE), CAST(int AS DECIMAL)`, `CAST(int AS STRING)`, `CAST(int AS TIME)`, `CAST(double AS INT)`, `CAST(double AS DECIMAL)`, `CAST(double AS STRING)`, `CAST(double AS TIME)`, `CAST(string AS INT)`, `CAST(string AS DOUBLE), CAST(string AS DECIMAL)`, `CAST(string AS TIME)`, `CAST(decimal AS INT)`, `CAST(decimal AS STRING)`, `CAST(decimal AS TIME)`, `CAST(decimal AS DOUBLE)`, `CAST(time AS INT)`, `CAST(time AS DECIMAL)`, `CAST(time AS STRING)`, `CAST(time AS REAL)`, `CAST(json AS JSON)`, `CAST(json AS STRING)`, `CAST(int AS JSON)`, `CAST(real AS JSON)`, `CAST(decimal AS JSON)`, `CAST(string AS JSON)`, `CAST(time AS JSON)`, `CAST(duration AS JSON)` |
-| [Aggregate functions](/functions-and-operators/aggregate-group-by-functions.md) | `MIN()`, `MAX()`, `SUM()`, `COUNT()`, `AVG()`, `APPROX_COUNT_DISTINCT()`, `GROUP_CONCAT()` |
+| [Aggregate functions](/functions-and-operators/aggregate-group-by-functions.md) | `MIN()`, `MAX()`, `SUM()`, `SUM_INT()`, `COUNT()`, `AVG()`, `APPROX_COUNT_DISTINCT()`, `GROUP_CONCAT()` |
 | [Miscellaneous functions](/functions-and-operators/miscellaneous-functions.md) | `INET_NTOA()`, `INET_ATON()`, `INET6_NTOA()`, `INET6_ATON()` |
 
 ## Restrictions