Bug #36466: Adding days to day_microsecond changes interpretation of microseco

      
When less than six places are given for microseconds, we zerofill from
the right (leftmost place is always 1/10s). We only did this when all
announced date/time fields were given; now we also format fractional
seconds when more significant fields are left out.

mysql-test/r/func_time.result

@@ -1301,6 +1301,12 @@ SELECT '2008-02-18' + INTERVAL 1 FRAC_SECOND;
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FRAC_SECOND' at line 1
 SELECT '2008-02-18' - INTERVAL 1 FRAC_SECOND;
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FRAC_SECOND' at line 1
+select date_add('1000-01-01 00:00:00', interval '1.03:02:01.05' day_microsecond);
+date_add('1000-01-01 00:00:00', interval '1.03:02:01.05' day_microsecond)
+1000-01-02 03:02:01.050000
+select date_add('1000-01-01 00:00:00', interval '1.02' day_microsecond);
+date_add('1000-01-01 00:00:00', interval '1.02' day_microsecond)
+1000-01-01 00:00:01.020000
 End of 5.0 tests
 select date_sub("0050-01-01 00:00:01",INTERVAL 2 SECOND);
 date_sub("0050-01-01 00:00:01",INTERVAL 2 SECOND)

mysql-test/t/func_time.test

@@ -819,6 +819,16 @@ SELECT '2008-02-18' + INTERVAL 1 FRAC_SECOND;
 --error ER_PARSE_ERROR
 SELECT '2008-02-18' - INTERVAL 1 FRAC_SECOND;
 
+#
+# Bug #36466:
+#   Adding days to day_microsecond changes interpretation of microseconds
+#
+
+# show that we treat fractions of seconds correctly (zerofill from right to
+# six places) even if we left out fields on the left.
+select date_add('1000-01-01 00:00:00', interval '1.03:02:01.05' day_microsecond);
+select date_add('1000-01-01 00:00:00', interval '1.02' day_microsecond);
+
 --echo End of 5.0 tests
 
 #

sql/item_timefunc.cc

@@ -865,6 +865,8 @@ static bool get_interval_info(const char *str,uint length,CHARSET_INFO *cs,
 {
   const char *end=str+length;
   uint i;
+  long msec_length= 0;
+
   while (str != end && !my_isdigit(cs,*str))
     str++;
 
@@ -874,12 +876,7 @@ static bool get_interval_info(const char *str,uint length,CHARSET_INFO *cs,
     const char *start= str;
     for (value=0; str != end && my_isdigit(cs,*str) ; str++)
       value= value*LL(10) + (longlong) (*str - '0');
-    if (transform_msec && i == count - 1) // microseconds always last
-    {
-      long msec_length= 6 - (uint) (str - start);
-      if (msec_length > 0)
-	value*= (long) log_10_int[msec_length];
-    }
+    msec_length= 6 - (str - start);
     values[i]= value;
     while (str != end && !my_isdigit(cs,*str))
       str++;
@@ -893,6 +890,10 @@ static bool get_interval_info(const char *str,uint length,CHARSET_INFO *cs,
       break;
     }
   }
+
+  if (transform_msec && msec_length > 0)
+    values[count - 1] *= (long) log_10_int[msec_length];
+
   return (str != end);
 }