Prior 12 Months

Question

Hi ,
I have a table that contains the Oraganization ,Month and Year Columns .Kindly help with a query to retrieve Prior 12 Months From current month from the table data . Data example Like below
So for example current month is May year 2014 . As per the data its available only for the prior 9 months so 9 months should be displayed . In short maximum of 12 months and min depending upon the data available from the current month .
Oraganization  
Month 
Year
Xyz
9
2013
wed
10
2013
dfs
11
2013
gfh
12
2013
try
1
2014
uyuo
2
2014
edgvf
3
2014
wesdv
4
2014
srsfsr
5
2014
sdcdsfcx
6
2014
srrgvcvbb
7
2014
qwwfe
8
2014
Thanks
Priya

Answer 1

Please post DDL, so that people do not have to guess what the keys, constraints, Declarative Referential Integrity, data types, etc. in your schema are. Learn how to follow ISO-11179 data element naming conventions and formatting rules. Temporal data should
use ISO-8601 formats. Code should be in Standard SQL as much as possible and not local dialect. 
This is minimal polite behavior on SQL forums. 
Your rude narrative has a design flaw called “attribute splitting”; in Standard SQL, we have interval data types and that would mean that you want INTERVAL YEAR TO MONTH for one columns.
Microsoft is behind the standards. 
Since SQL is a database language, we prefer to do look ups and not calculations. They can be optimized while temporal math messes up optimization. A useful idiom is a report period calendar that everyone uses so there is no way to get disagreements in the DML.
The report period table gives a name to a range of dates that is common to the entire enterprise. 
CREATE TABLE Prior_Year_Periods
(month_name CHAR(10) NOT NULL PRIMARY KEY
   CHECK (month_name LIKE '[12][0-9][0-9][0-9]-[01][0-9]-00'),
 month_start_date DATE NOT NULL,
 month_end_date DATE NOT NULL,
  CONSTRAINT date_ordering
    CHECK (month_start_date <= month_end_date),
etc);
These report periods can overlap or have gaps. I like the MySQL convention of using double zeroes for months and years, That is 'yyyy-mm-00' for a month within a year and 'yyyy-00-00' for the whole calendar year. The advantages are that it will sort with the
ISO-8601 data format required by Standard SQL and it is language independent. 
Your report period is a month with an ending date 12 month ago. Your example is one row: 
INSERT INTO Prior_Year_Periods 
('2014-08-00', '2013-09-01',  '2014-08-31'),
Now use a simple BETWEEN predicate in your query. 
Here is my guess at what you should have posted. 
CREATE TABLE Foobars
(organization_name VARCHAR(25) NOT NULL PRIMARY KEY,
 foobar_month CHAR(10) NOT NULL 
  REFERENCES Month_Periods (month_name));
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