Counting if data exists in a row - sql

Question

Hey guys I have the below sample data which i want to query for.
MemberID AGEQ1 AGEQ2 AGEQ2
-----------------------------------------------------------------
1217 2 null null
58458 3 2 null
58459 null null null
58457 null 5 null
299576 6 5 7
What i need to do is to lookup the table and if any AGEx COLUMN contains any data then it counts the number of times there is data for that row in each column
Results example:
for memberID 1217 the count would be 1
for memberID 58458 the count would be 2
for memberID 58459 the count would be 0 or null
for memberID 58457 the count would be 1
for memberID 299576 the count would be 3
This is how it should look like in SQL if i query the entire table
1 Children - 2
2 Children - 1
3 Children - 1
0 Children - 1
So far i have been doing it using the following query which isnt very efficient and does give incorrect tallies as there are multiple combinations that people can answer the AGE question. Also i have to write multiple queries and change the is null to is not null depending on how many children i am looking to count a person has
select COUNT (*) as '1 Children' from Member
where AGEQ1 is not null
and AGEQ2 is null
and AGEQ3 is null
The above query only gives me an answer of 1 but i want to be able to count the other columns for data as well
Hope this is nice and clear and thank you in advance

Answer 1

If all of the columns are integers, you can take advantage of integer math - dividing the column by itself will yield 1, unless the value is NULL, in which case COALESCE can convert the resulting NULL to 0.
SELECT
MemberID,
COALESCE(AGEQ1 / AGEQ1, 0)
+ COALESCE(AGEQ2 / AGEQ2, 0)
+ COALESCE(AGEQ3 / AGEQ3, 0)
+ COALESCE(AGEQ4 / AGEQ4, 0)
+ COALESCE(AGEQ5 / AGEQ5, 0)
+ COALESCE(AGEQ6 / AGEQ6, 0)
FROM dbo.table_name;
To get the number of people with each count of children, then:
;WITH y(y) AS
(
SELECT TOP (7) rn = ROW_NUMBER() OVER
(ORDER BY [object_id]) - 1 FROM sys.objects
),
x AS
(
SELECT
MemberID,
x = COALESCE(AGEQ1 / AGEQ1, 0)
+ COALESCE(AGEQ2 / AGEQ2, 0)
+ COALESCE(AGEQ3 / AGEQ3, 0)
+ COALESCE(AGEQ4 / AGEQ4, 0)
+ COALESCE(AGEQ5 / AGEQ5, 0)
+ COALESCE(AGEQ6 / AGEQ6, 0)
FROM dbo.table_name
)
SELECT
NumberOfChildren = y.y,
NumberOfPeopleWithThatMany = COUNT(x.x)
FROM y LEFT OUTER JOIN x ON y.y = x.x
GROUP BY y.y ORDER BY y.y;

Answer 2

I'd look at using UNPIVOT. That will make your wide column into rows. Since you don't care about what value was in a column, just the presence/absence of value, this will generate a row per not-null column.
The trick then becomes mashing that into the desired output format. It could probably have been done cleaner but I'm a fan of "showing my work" so that others can conform it to their needs.
SQLFiddle
-- Using the above logic
WITH HadAges AS
(
-- Find everyone and determine number of rows
SELECT
UP.MemberID
, count(1) AS rc
FROM
dbo.Member AS M
UNPIVOT
(
ColumnValue for ColumnName in (AGEQ1, AGEQ2, AGEQ3)
) AS UP
GROUP BY
UP.MemberID
)
, NoAge AS
(
-- Account for those that didn't show up
SELECT M.MemberID
FROM
dbo.Member AS M
EXCEPT
SELECT
H.MemberID
FROM
HadAges AS H
)
, NUMBERS AS
(
-- Allowable range is 1-6
SELECT TOP 6
ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS TheCount
FROM
sys.all_columns AS SC
)
, COMBINATION AS
(
-- Link those with rows to their count
SELECT
N.TheCount AS ChildCount
, H.MemberID
FROM
NUMBERS AS N
LEFT OUTER JOIN
HadAges AS H
ON H.rc = N.TheCount
UNION ALL
-- Deal with the unlinked
SELECT
0
, NA.MemberID
FROM
NoAge AS NA
)
SELECT
C.ChildCount
, COUNT(C.MemberID) AS Instances
FROM
COMBINATION AS C
GROUP BY
C.ChildCount;

Answer 3

Try this:
select id, a+b+c+d+e+f
from ( select id,
case when age1 is null then 0 else 1 end a,
case when age2 is null then 0 else 1 end b,
case when age3 is null then 0 else 1 end c,
case when age4 is null then 0 else 1 end d,
case when age5 is null then 0 else 1 end e,
case when age6 is null then 0 else 1 end f
from ages
) as t
See here in fiddle http://sqlfiddle.com/#!3/88020/1
To get the quantity of persons with childs
select childs, count(*) as ct
from (
select id, a+b+c+d+e+f childs
from
(
select
id,
case when age1 is null then 0 else 1 end a,
case when age2 is null then 0 else 1 end b,
case when age3 is null then 0 else 1 end c,
case when age4 is null then 0 else 1 end d,
case when age5 is null then 0 else 1 end e,
case when age6 is null then 0 else 1 end f
from ages ) as t
) ct
group by childs
order by 1
See it here at fiddle http://sqlfiddle.com/#!3/88020/24