Find an average age range over a span of ages - mysql

Question

I need to find the most occurrences in a 10yr age range that can be Age 2 to 22, 15 to 25, 10 to 20, etc. in a table with name & age
I've created the SQL that returns the average age:
SELECT age, count(age)
FROM member
GROUP BY age
ORDER BY COUNT(age) DESC
LIMIT 1
Thanks for your help!

Answer 1

Create another table ages to hold the age ranges you are interested in with a field for age_lower, age_upper and a display name age_range such as '2 to 22'
Join the tables with a WHERE clause that puts the age between the lower and upper ranges.
SELECT `age_range`, COUNT(`age`) AS age_count
FROM `member` INNER JOIN `ages`
ON age BETWEEN age_lower AND age_upper
GROUP BY age_range
ORDER BY COUNT(`age`) DESC, `age_range` ASC
SQL Fiddle

Answer 2

This might solve the problem. The only thing I added was a table to hold values 1..x where x is your bucket count. The #T can easily be replaced with your MySQL table name. The results are all possible sets the age falls in, for each age. Then count of how many equal sets.
--IGNORE BUILDING TEST DATA IN SQL SERVER
DECLARE #T TABLE(member INT,age INT)
DECLARE #X INT
SET #X=1
WHILE(#X<=100) BEGIN
INSERT INTO #T SELECT #X, CAST(RAND() * 100 AS INT)
SET #X=#X+1
END
DECLARE #MinAge INT=1
DECLARE #MaxAge INT=100
--YOUR SET TABLE. TO MAKE LIFE EASY YOU NEED A TABLE OF 1..X
DECLARE #SET TABLE (Value INT)
DECLARE #SET_COUNT INT =10
DECLARE #LOOP INT=1
WHILE(#LOOP<=#SET_COUNT) BEGIN
INSERT #SET SELECT #LOOP
SET #LOOP=#LOOP+1
END
SELECT
MinAge,
MaxAge,
SetCount=COUNT(CountFlag)
FROM
(
SELECT
MinAge=AgeMinusSetCount,
MaxAge=AgePlusSetCount,
CountFlag=1
FROM
(
SELECT DISTINCT
ThisAge,
AgeMinusSetCount=(AgeMinusSetCount-1) + Value,
AgePlusSetCount=CASE WHEN (AgeMinusSetCount-1) + Value + #SET_COUNT > #MaxAge THEN #MaxAge ELSE (AgeMinusSetCount-1) + Value + #SET_COUNT END
FROM
(
SELECT
ThisAge=age,
AgeMinusSetCount=CASE WHEN (age - #SET_COUNT) < #MinAge THEN #MinAge ELSE (age) - #SET_COUNT END
FROM
#T
)RANGES
LEFT OUTER JOIN (SELECT Value FROM #SET) AS FanLeft ON 1=1
)AS DETAIL
)AS Summary
GROUP BY
MinAge,
MaxAge
ORDER BY
COUNT(CountFlag) DESC