[bug](function) fix milliseconds_diff function return wrong result (a…

…pache#32897)

* [bug](function) fix milliseconds_diff function return wrong result

be/src/vec/functions/function_date_or_datetime_computation.h

@@ -315,15 +315,25 @@ struct TimeDiffImpl {
 
     static constexpr auto name = "timediff";
     static constexpr auto is_nullable = false;
-    static inline ReturnType ::FieldType execute(const ArgType1& t0, const ArgType2& t1,
-                                                 bool& is_null) {
+    static constexpr int64_t limit_value = 3020399000000; // 838:59:59 convert to microsecond
+    static inline ReturnType::FieldType execute(const ArgType1& t0, const ArgType2& t1,
+                                                bool& is_null) {
         const auto& ts0 = reinterpret_cast<const DateValueType1&>(t0);
         const auto& ts1 = reinterpret_cast<const DateValueType2&>(t1);
         is_null = !ts0.is_valid_date() || !ts1.is_valid_date();
         if constexpr (UsingTimev2) {
-            return ts0.microsecond_diff(ts1);
+            // refer to https://dev.mysql.com/doc/refman/5.7/en/time.html
+            // the time type value between '-838:59:59' and '838:59:59', so the return value should limited
+            int64_t diff_m = ts0.microsecond_diff(ts1);
+            if (diff_m > limit_value) {
+                return (double)limit_value;
+            } else if (diff_m < -1 * limit_value) {
+                return (double)(-1 * limit_value);
+            } else {
+                return (double)diff_m;
+            }
         } else {
-            return (1000 * 1000) * ts0.second_diff(ts1);
+            return (double)((1000 * 1000) * ts0.second_diff(ts1));
         }
     }
     static DataTypes get_variadic_argument_types() {

be/src/vec/runtime/vdatetime_value.h

@@ -1111,13 +1111,13 @@ class DateV2Value {
         return (daynr() - rhs.daynr()) * SECOND_PER_HOUR * HOUR_PER_DAY + time_part_diff(rhs);
     }
 
+    // used by INT microseconds_diff(DATETIME enddate, DATETIME startdate)
+    // return it's int type, so shouldn't have any limit.
+    // when used by TIME TIMEDIFF(DATETIME expr1, DATETIME expr2), it's return time type, should have limited.
     template <typename RHS>
-    double microsecond_diff(const RHS& rhs) const {
+    int64_t microsecond_diff(const RHS& rhs) const {
         int64_t diff_m = (daynr() - rhs.daynr()) * SECOND_PER_HOUR * HOUR_PER_DAY * 1000 * 1000 +
                          time_part_diff_microsecond(rhs);
-        if (diff_m > (int64_t)3020399 * 1000 * 1000) {
-            diff_m = (int64_t)3020399 * 1000 * 1000;
-        }
         return diff_m;
     }
 

docs/en/docs/sql-manual/sql-functions/date-time-functions/timediff.md

@@ -34,8 +34,8 @@ under the License.
 TIMEDIFF returns the difference between two DATETIMEs
 
 The TIMEDIFF function returns the result of expr1 - expr2 expressed as a time value, with a return value of TIME type
-
-The results are limited to TIME values ranging from - 838:59:59 to 838:59:59.
+Due to the valid range of TIME type being '-838:59:59' to '838:59:59',
+So when the return value of the calculation result is less than the left boundary or greater than the right boundary, the corresponding boundary value will be taken.
 
 #### example
 
@@ -60,6 +60,13 @@ mysql> SELECT TIMEDIFF('2019-01-01 00:00:00', NULL);
 +---------------------------------------+
 | NULL                                  |
 +---------------------------------------+
+
+mysql >SELECT timediff('2020-02-02 15:30:00', '1951-02-16 15:27:00') as res;
++-----------+
+| res       |
++-----------+
+| 838:59:59 |
++-----------+
 ```
 ### keywords
     TIMEDIFF

docs/zh-CN/docs/sql-manual/sql-functions/date-time-functions/timediff.md

@@ -33,7 +33,8 @@ under the License.
 
 TIMEDIFF返回两个DATETIME之间的差值
 
-TIMEDIFF函数返回表示为时间值的expr1 - expr2的结果，返回值为TIME类型
+TIMEDIFF函数返回表示为时间值的expr1 - expr2的结果，返回值为TIME类型, 由于TIME类型的合法有效范围为'-838:59:59' to '838:59:59',
+所以当计算结果的返回值小于左边界或大于右边界时，会取对应的边界值.
 
 ### example
 
@@ -58,6 +59,13 @@ mysql> SELECT TIMEDIFF('2019-01-01 00:00:00', NULL);
 +---------------------------------------+
 | NULL                                  |
 +---------------------------------------+
+
+mysql >SELECT timediff('2020-02-02 15:30:00', '1951-02-16 15:27:00') as res;
++-----------+
+| res       |
++-----------+
+| 838:59:59 |
++-----------+
 ```
 
 ### keywords