Query not displaying the week value as 0 - sql

Question

SELECT datediff(week, dateadd(week, datediff(week, 0, dateadd(month, datediff(month, 0, EntryDate), 0)), 0), EntryDate - 1) + 1 as week,
count(UserID) as balance
FROM table_points
where right(convert(varchar, EntryDate, 106), 8)='Mar 2015'
GROUP BY datediff(week, dateadd(week, datediff(week, 0, dateadd(month, datediff(month, 0, EntryDate), 0)), 0), EntryDate - 1) + 1
When i execute this query i get result for 4th and 5th week values but not for others week. Like
week balance
4 80
5 100
In first 3 weeeks there is no values in database so it will not showing the values . Can any one bring 0 value for 1st , 2nd and 3rd week.
I want result as
week balance
1 0
2 0
3 0
4 80
5 100
can any one help me out.

Answer 1

Create a calendar/date table, including all possible dates/weeks, and from there left join the table_points table.
If no data is present in table_points, it will return 0 for those weeks.
If no dates are present in a table, it's impossible to select these and get a zero.
Example:
SELECT d.week, count(t.UserID)
FROM dates d left join table_points t on
d.date = t.EntryDate
where right(convert(varchar, d.date, 106), 8)='Mar 2015'
group by d.week
A date table can be very useful for many applications and could be filled like:
date week year month WeekOfMonth DayOfWeek Day Month
2015-03-01 18 2015 3 1 5 Friday March
2015-03-02 18 2015 3 1 6 Friday March
2015-03-03 18 2015 3 1 7 Sunday March
2015-03-04 19 2015 3 2 1 Monday March

Answer 2

This works like PSVSupporter's solution but uses a CTE to get a date list instead of using another table:
;WITH Dates AS (
SELECT
[Date] = CONVERT(DATETIME,'03/01/2015')
UNION ALL SELECT
[Date] = DATEADD(DAY, 1, [Date])
FROM
Dates
WHERE
Date < '03/31/2015'
)
SELECT
datediff(week, dateadd(week, datediff(week, 0, dateadd(month, datediff(month, 0, ds.Date), 0)), 0), ds.Date - 1) + 1 as week,
count(tp.UserID) as balance
FROM Dates ds
left join table_points tp on tp.EntryDate = ds.Date
WHERE right(convert(varchar, ds.Date, 106), 8)='Mar 2015'
GROUP BY datediff(week, dateadd(week, datediff(week, 0, dateadd(month, datediff(month, 0, ds.Date), 0)), 0), ds.Date - 1) + 1
I took CTE from https://stackoverflow.com/a/7824893/3309109