Insert Missing Dates from a query

How can i insert missing dates from a query i created. The result below:

Date          Frequency
2014-05-18    5
2014-05-20    7
2014-05-25    7
2014-05-27    6

I want the result to have missing dates with 0 value as shown below:

Date          Frequency
2014-05-18    5
2014-05-19    0
2014-05-20    7
2014-05-21    0
2014-05-22    0
2014-05-23    0
2014-05-24    0
2014-05-25    7
2014-05-26    0
2014-05-27    6

Please note that I have read only access to the server.

Here is an example using a calendar table (which you really should have). This example just populates 2014 but you can stuff it with as many years as you like...

CREATE TABLE dbo.Calendar(d DATE PRIMARY KEY);

INSERT dbo.Calendar(d) SELECT TOP (365)
 DATEADD(DAY, ROW_NUMBER() OVER (ORDER BY number)-1, '20140101')
 FROM [master].dbo.spt_values
 WHERE [type] = N'P' ORDER BY number;

Now the query is simple:

DECLARE @s DATE = '20140518', @e DATE = '20140527';

SELECT c.d, Frequency = COALESCE(s.Frequency,0)
  FROM dbo.Calendar AS c
  LEFT OUTER JOIN dbo.splunge AS s
  ON c.d = s.[date]
  WHERE c.d >= @s
    AND c.d < DATEADD(DAY, 1, @e);

db<>fiddle example

If you can't create a calendar table (and don't have a numbers table handy either), then you can just put it inline:

DECLARE @s DATE = '20140518', @e DATE = '20140527';

SELECT c.d, Frequency = COALESCE(s.Frequency,0)
  FROM 
(
   SELECT TOP (DATEDIFF(DAY, @s, @e)+1)
 DATEADD(DAY, ROW_NUMBER() OVER (ORDER BY number)-1, @s)
 FROM [master].dbo.spt_values
 WHERE [type] = N'P' ORDER BY number
) AS c(d)
  LEFT OUTER JOIN dbo.splunge2 AS s
  ON c.d = s.[date]
  WHERE c.d >= @s
    AND c.d < DATEADD(DAY, 1, @e);

db<>fiddle example

For more on generating sets (of dates, numbers, etc.) see this series:

• Generate a set or sequence without loops – part 1

• Generate a set or sequence without loops – part 2

• Generate a set or sequence without loops – part 3

And more on calendar tables:

• Creating a date dimension or calendar table

• Using a Calendar Table - Part 1

StackExchange Database Administrators Q#75473, answer score: 15