Count days between two dates excluding weekends

Question

How can I find the difference between two dates in DB2 (excluding weekends)?

Are there any functions that will do this in DB2? Or do I need to write a query myself?

Answer 1

There is AFAIK no such function. It is however easy to write a query that calculates this:

with cal(d) as ( 
    values date('2015-01-01') -- start_date 
    union all 
    select d + 1 day from cal 
    where d < '2015-01-15'    -- end_date 
) select count(case when dayofweek(d) between 2 and 6 then 1 end) 
  from cal;

If you do a lot of these kind of calculations you might want to create a calendar table, you can add attributes like national holiday etc to this table.

Answer 2

you can use this function:

DAYOFWEEK(CURRENT_DATE)

The following calculation will return the number of working days between two dates:

[Week(End Date) - Week(Start Date)] * 5 + [DayofWeek(Start Date) - DayofWeek(End Date)]

This will only work if the functions for Week and Day or equivalent are native to the database driver. Client Access and Sybase native connection both support these functions.

The Week function will give the integer value of the week of the year selected. The DayofWeek will give an Integer value from 1-7 for the day selected.

IBM Support Working Days Between Two Dates

Answer 3

This is the best way to implement difference between two dates excluding weekend means Saturday and Sunday and also excluding national holiday....

  /******
   * First, we'll extend the date object with some functionality.
   *   We'll add an  .each() function, as well as an .adjust() function.
   *   .each()  will give us the ability to loop between two dates, whether
   *     by 'day', 'week' or 'month'.
   *   .adjust() will allow us to move a given day by a given unit. This is used
   *     like so: currentDate.adjust('days', 1) to increment by one day.
   ******/
  Date.prototype.each = function(endDate, part, step, fn, bind){
   var fromDate = new Date(this.getTime()),
    toDate = new Date(endDate.getTime()),
    pm = fromDate <= toDate? 1:-1,
    i = 0;

   while( (pm === 1 && fromDate <= toDate) || (pm === -1 && fromDate >= toDate) ){
    if(fn.call(bind, fromDate, i, this) === false) break;
    i += step;
    fromDate.adjust(part, step*pm);
   }
   return this;
  };
  
  Date.prototype.adjust = function(part, amount){
 part = part.toLowerCase();
 
 var map = { 
    years: 'FullYear', months: 'Month', weeks: 'Hours', days: 'Hours', hours: 'Hours', 
    minutes: 'Minutes', seconds: 'Seconds', milliseconds: 'Milliseconds',
    utcyears: 'UTCFullYear', utcmonths: 'UTCMonth', weeks: 'UTCHours', utcdays: 'UTCHours', 
    utchours: 'UTCHours', utcminutes: 'UTCMinutes', utcseconds: 'UTCSeconds', utcmilliseconds: 'UTCMilliseconds'
   },
  mapPart = map[part];

 if(part == 'weeks' || part == 'utcweeks')
  amount *= 168;
 if(part == 'days' || part == 'utcdays')
  amount *= 24;
 
 this['set'+ mapPart]( this['get'+ mapPart]() + amount );

 return this;
}
  
  
/*******
 * An array of national holidays. This is used to test for the exclusion of given
 *   days. While this list is national days, you could tailor it to regional, state
 *   or given religious observances. Whatever.
 ******/
natDays = [
  {
    month: 1,
    date: 26,
    type: "national - us",
    name: "New Year's Day"
  },
  {
    month: 1,
    date: 21,
    type: "national - us",
    name: "Martin Luther King Day"
  },
  {
    month: 2,
    date: 18,
    type: "national - us",
    name: "President's Day (Washington's Birthday"
  },
  {
    month: 5,
    date: 27,
    type: "national - us",
    name: "Memorial Day"
  },
  {
    month: 7,
    date: 4,
    type: "national - us",
    name: "Independence Day"
  },
  {
    month: 9,
    date: 2,
    type: "national - us",
    name: "Labor Day"
  },
  
  {
    month: 10,
    date: 14,
    type: "national - us",
    name: "Columbus Day"
  },
  {
    month: 11,
    date: 11,
    type: "national - us",
    name: "Veteran's Day"
  },
  {
    month: 11,
    date: 29,
    type: "national - us",
    name: "Thanksgiving Day"
  },
  {
    month: 12,
    date: 25,
    type: "national - us",
    name: "Christmas Day"
  }
  
];

/******
 * This uses the national holidays array we just set, and checks a given day to see
 *   if it's in the list. If so, it returns true and the name of the holiday, if not
 *   it returns false.
 *****/
function nationalDay(date) {
    for (i = 0; i < natDays.length; i++) {
      if (date.getMonth() == (natDays[i].month-1)
          && date.getDate() == natDays[i].date) {
        return [true, natDays[i].name];
      }
    }
  return [false, null];
}

/******
 * This function takes two dates, as start and end date, and iterates through the
 *   dates between them. For each date, it checks if the current date is a week day.
 *   If it is, it then checks if it isn't a holiday. In this case, it increments
 *   the business day counter.
 ******/
function calcBusinessDays(startDate, endDate) {
  // input given as Date objects
  var iDateDiff=0, holidays = [];
    
  startDate.each(endDate, 'days', 1, function(currentDate, currentStep, thisDate){
      if(currentDate.getDay() != 0 && currentDate.getDay() != 6 ) {
        var isAHoliday = nationalDay(currentDate);
          if(!isAHoliday[0]){
            iDateDiff += 1;
          } else {
            holidays.push(isAHoliday[1]);
          }
      }
   });
   return {count: iDateDiff, holidays: holidays};

};

$(function(){
  var results, exclusions;

$( "#startDate" ).datepicker({
      defaultDate: "+1w",
      changeMonth: true,
      numberOfMonths: 3,
      onClose: function( selectedDate ) {
        $( "#endDate" ).datepicker( "option", "minDate", selectedDate );
      }
    });
    $( "#endDate" ).datepicker({
      defaultDate: "+1w",
      changeMonth: true,
      numberOfMonths: 3,
      onClose: function( selectedDate ) {
        $( "#startDate" ).datepicker( "option", "maxDate", selectedDate );
      }
    });
    $("#calculateMe").on("click", function(){
      var startDate = new Date($("#startDate").val()),
          endDate = new Date($("#endDate").val() );
      // Calculate the number of business days. This returns an object, with
      //  two members: count and holidays
      results = calcBusinessDays(startDate, endDate);
      exclusions = "Excluded weekends";
      if (results.holidays.length > 0) {
        // We have holidays, tell the user about them...
        exclusions += " and the following holidays: ";
        for(var i=0; i<results.holidays.length; i += 1){
          exclusions += results.holidays[i]+", ";
        }
      } else {
        // No holidays.
        exclusions += ".";
      }
      $("#result").text(results.count + " business days." ).append("<p>("+exclusions+")</p>");
    });
});

<div id="content">
    <input type="text" class="myDateClass" id="startDate"/>    
    <input type="text" class="myDateClass" id="endDate"/>
    <button id="calculateMe">How many business days?</button>
    <div id="result"></div>
</div>

Fiddle