SQL select, pad with chronological missing months

Question

Notice the 2015-02 and 2015-03 months are missing in the output from the following group by SQL. If there is no data for a month I wan

Answer 1

If you don't want to go beyond your min and max dates of your results then you can do the following:

WITH    cte
          AS ( SELECT convert(char(7), MeterReadDate, 121) AS [Date], COUNT(*) AS [Count]
               FROM [myTable]
               WHERE (MeterReadDate > dateadd(d,-356,getdate()))
               GROUP by  convert(char(7), MeterReadDate, 121)
             ),
        minmax
          AS ( SELECT   CAST(MIN([Date] + '-01') AS DATE) AS mind ,
                        CAST(MAX([Date] + '-01') AS DATE) maxd
               FROM     cte
             ),
        calendar
          AS ( SELECT   mind ,
                        CONVERT(CHAR(7), mind, 121) AS cmind
               FROM     minmax
               UNION ALL
               SELECT   DATEADD(mm, 1, calendar.mind) ,
                        CONVERT(CHAR(7), DATEADD(mm, 1, calendar.mind), 121)
               FROM     calendar
                        CROSS JOIN minmax
               WHERE    calendar.mind < minmax.maxd
             )
    SELECT  c.cmind AS [Date],
            ISNULL(cte.[Count], 0) AS [Count]
    FROM    calendar c
            LEFT JOIN cte ON c.cmind = cte.[Date]
    OPTION  ( MAXRECURSION 0 )