MySQL: Count of records with consecutive months

Question

I\'ve searched around for this, but all the similar questions and answers are just different enough not to work.

I have a table with the following fields: person, th

Answer 1

I used this StackOverflow answer for guidance (Check for x consecutive days - given timestamps in database)

SELECT a.person, COUNT(1) AS consecutive_months
FROM
(

  SELECT a.person, IF(b.YearMonth IS NULL, @val:=@val+1, @val) AS consec_set
  FROM (
    SELECT DISTINCT person, EXTRACT(YEAR_MONTH from purdate) as YearMonth from records
    ) a
  CROSS JOIN (SELECT @val:=0) var_init
  LEFT JOIN (SELECT DISTINCT person, EXTRACT(YEAR_MONTH from purdate) as YearMonth from records) b ON
      a.person = b.person AND
      a.YearMonth = b.YearMonth + 1
   ) a
GROUP BY a.consec_set
HAVING COUNT(1) >= 2    

Here is the SQLFiddle - http://sqlfiddle.com/#!2/cc5c3/55