diff --git a/core/sql/exp/exp_datetime.cpp b/core/sql/exp/exp_datetime.cpp
index 926cde2401..6c1e8b0540 100644
--- a/core/sql/exp/exp_datetime.cpp
+++ b/core/sql/exp/exp_datetime.cpp
@@ -3686,6 +3686,8 @@ ExpDatetime::convDatetimeToASCII(char *srcData,
         {
           if (hour > 12)
             hour = hour - 12;
+          if ( 0 == hour )
+            hour = 12;
         }
       convertToAscii(hour, dstDataPtr, 2);
       return (dstDataPtr - dstData);
@@ -3809,10 +3811,8 @@ ExpDatetime::convDatetimeToASCII(char *srcData,
       int weekofmonth = 0;
       if ( day )
         {
-          Int64 interval = getTotalDays(year, 1, 1);
-          int dayofweek = (int)(((interval + 1) % 7) + 1);
           int dayofyear = Date2Julian(year,month,day)-Date2Julian(year,1,1)+1;
-          weekofmonth = (dayofyear-1+dayofweek-1)/7+1;
+          weekofmonth = (dayofyear-1)/7+1;
         }
       convertToAscii(weekofmonth,dstDataPtr,2);
       return (dstDataPtr - dstData);
diff --git a/core/sql/exp/exp_function.cpp b/core/sql/exp/exp_function.cpp
index 85a5fbf4af..1685b9c1b8 100644
--- a/core/sql/exp/exp_function.cpp
+++ b/core/sql/exp/exp_function.cpp
@@ -3034,6 +3034,11 @@ static Int64 lcl_interval(rec_datetime_field eField, Lng32 eCode, char *opdata,
     {
       short nValue;
       str_cpy_all((char *) &nValue, opdata, sizeof(nValue));
+      if ( 0 == nValue )
+        return 1;
+      nValue = nValue % 12;
+      if ( 0 == nValue )
+        return 4;
       return (nValue-1)/3+1;
     }
   if ( REC_DATE_EPOCH == eField )
@@ -3173,11 +3178,9 @@ Int64 ex_function_extract::getExtraTimeValue(rec_datetime_field eField, Lng32 eC
           return year/10;
         }
       case REC_DATE_WEEK:
-        {//same with built-in function week  ITM_WEEK
-          Int64 interval = datetimeOpType->getTotalDays(year, 1, 1);
-          Int64 dayofweek = lcl_dayofweek(interval);
+        {
           Int64 dayofyear = lcl_dayofyear(year,month,day);
-          return (dayofyear-1+dayofweek-1)/7+1;
+          return (dayofyear-1)/7+1;
         }
       case REC_DATE_QUARTER:
         {