diff -Nur sql/item_create.cc ../mysql-5.0.21-patched/sql/item_create.cc
--- sql/item_create.cc	2006-04-26 20:30:56.000000000 +0200
+++ ../mysql-5.0.21-patched/sql/item_create.cc	2007-05-19 01:00:45.000000000 +0200
@@ -681,6 +681,11 @@
 			     new Item_func_to_days(b));
 }
 
+Item *create_func_workdays(Item* a,Item* b)
+{
+  return new Item_func_workdays(a, b);
+}
+
 Item *create_func_weekofyear(Item *a)
 {
   return new Item_func_week(a, new Item_int((char*) "0", 3, 1));
diff -Nur sql/item_create.h ../mysql-5.0.21-patched/sql/item_create.h
--- sql/item_create.h	2006-04-26 20:30:48.000000000 +0200
+++ ../mysql-5.0.21-patched/sql/item_create.h	2007-05-19 01:06:43.000000000 +0200
@@ -98,6 +98,7 @@
 Item *create_func_uuid(void);
 Item *create_func_version(void);
 Item *create_func_weekday(Item* a);
+Item *create_func_workdays(Item* a, Item* b);
 Item *create_load_file(Item* a);
 Item *create_func_is_free_lock(Item* a);
 Item *create_func_is_used_lock(Item* a);
diff -Nur sql/item_timefunc.cc ../mysql-5.0.21-patched/sql/item_timefunc.cc
--- sql/item_timefunc.cc	2006-04-26 20:31:09.000000000 +0200
+++ ../mysql-5.0.21-patched/sql/item_timefunc.cc	2007-05-19 01:40:41.000000000 +0200
@@ -875,6 +875,46 @@
 }
 
 
+longlong Item_func_workdays::val_int()
+{
+  DBUG_ASSERT(fixed == 1);
+  TIME lstarttime;
+  TIME lstoptime;
+
+  uint fuzzy_date;
+  args[0]->get_date(&lstarttime, fuzzy_date);
+  args[1]->get_date(&lstoptime,  fuzzy_date);
+
+  longlong days1 = calc_daynr(lstarttime.year,lstarttime.month,lstarttime.day);
+  longlong days2 = calc_daynr(lstoptime.year,lstoptime.month,lstoptime.day);
+  longlong nrofdays = days2 - days1;
+
+  if (nrofdays==0) return (longlong) 1;  // e.g. monday - monday = 1 day
+
+  bool neg_nrofdays = (nrofdays < 0);
+  int dayofweek = calc_weekday((neg_nrofdays ? days2 : days1), 0);
+  nrofdays = abs(nrofdays)+1; // e.g. diff mon-tue = 1, but takes 2 days
+
+  longlong nrofweekends = (longlong) floor(nrofdays / 7);
+  int mod = nrofdays % 7;
+  int add = 0;
+
+  // Correction when the remainder (part of a week)
+  // fully or partly comprises a weekend.
+  if (mod)
+  {
+     if ((dayofweek)==6) add=1;
+     else
+     {
+        add = mod - (5 - dayofweek);
+        if (add<0) add = 0;
+        if (add>1) add = 2;
+     }
+  }
+
+  return (longlong) (neg_nrofdays ? -1 : +1)*(nrofdays - ((nrofweekends*2) + add));
+}
+
 
 longlong Item_func_to_days::val_int()
 {
Binary files sql/.item_timefunc.cc.swp and ../mysql-5.0.21-patched/sql/.item_timefunc.cc.swp differ
diff -Nur sql/item_timefunc.h ../mysql-5.0.21-patched/sql/item_timefunc.h
--- sql/item_timefunc.h	2006-04-26 20:30:56.000000000 +0200
+++ ../mysql-5.0.21-patched/sql/item_timefunc.h	2007-05-19 01:10:32.000000000 +0200
@@ -67,6 +67,21 @@
   }
 };
 
+class Item_func_workdays :public Item_int_func
+{
+public:
+  Item_func_workdays(Item *a, Item *b) :Item_int_func(a, b) {}
+  longlong val_int();
+  const char *func_name() const { return "workdays"; }
+  void fix_length_and_dec() 
+  { 
+    decimals=0; 
+    max_length=6*MY_CHARSET_BIN_MB_MAXLEN;
+    maybe_null=1; 
+  }
+};
+
+
 
 class Item_func_dayofmonth :public Item_int_func
 {
diff -Nur sql/lex.h ../mysql-5.0.21-patched/sql/lex.h
--- sql/lex.h	2006-04-26 20:30:47.000000000 +0200
+++ ../mysql-5.0.21-patched/sql/lex.h	2007-05-19 00:24:46.000000000 +0200
@@ -588,6 +588,7 @@
   { "CURTIME",		SYM(CURTIME)},
   { "DATE_ADD",		SYM(DATE_ADD_INTERVAL)},
   { "DATEDIFF",		F_SYM(FUNC_ARG2),0,CREATE_FUNC(create_func_datediff)},
+  { "WORKDAYS",		F_SYM(FUNC_ARG2),0,CREATE_FUNC(create_func_workdays)},
   { "DATE_FORMAT",	F_SYM(FUNC_ARG2),0,CREATE_FUNC(create_func_date_format)},
   { "DATE_SUB",		SYM(DATE_SUB_INTERVAL)},
   { "DAYNAME",		F_SYM(FUNC_ARG1),0,CREATE_FUNC(create_func_dayname)},