Getting counts of row data - sql

Question

There's a table variable (I'll write it as a regular table here)
CREATE TABLE TEST (memberid int, producttype varchar(7))
This table has hundreds of thousands of rows, but for this example I've added a lot less
Insert into test values(1,'book')
Insert into test values(1,'clothes')
Insert into test values(2,'book')
Insert into test values(3,'book')
Insert into test values(4,'clothes')
Insert into test values(5,'book')
Insert into test values(5,'clothes')
Insert into test values(6,'book')
Insert into test values(7,'book')
I need to get:
the memberids that have 'book' only
the memberids that have 'clothes' only
the memberids that have both 'book' & 'clothes'
e.g.
Member Book Clothes Both
1 0 0 1
2 1 0 0
3 1 0 0
4 0 1 0
5 0 0 1
6 1 0 0
7 1 0 0
I had managed to get it to work with sub-queries, but because of the size of the table it could take over 2 minutes to run.
I would appreciate if anyone knows a better way to achieve this?

Answer 1

One method uses conditional aggregation:
select
memberid,
case when max(producttype) = 'book' then 1 else 0 end book,
case when min(producttype) = 'clothes' then 1 else 0 end clothes,
case when min(producttype) <> max(producttype) then 1 else 0 end both
from test
group by memberid
This works because there are only two possible producttypes. If you actually have more, then you need some expressions that are more complicated (and possibly more efficient), such as:
case when count(*) = sum(case when producttype = 'book' then 1 end)
then 1
else 0
end book

Answer 2

Use a CTE to get if each member has book and/or clothes:
with cte as (
select memberid,
count(distinct case when producttype = 'book' then 1 end) book_flag,
count(distinct case when producttype = 'clothes' then 1 end) clothes_flag
from test
group by memberid
)
select memberid,
case when book_flag > clothes_flag then 1 else 0 end book,
case when clothes_flag > book_flag then 1 else 0 end clothes,
book_flag * clothes_flag both
from cte
See the demo.
Results:
> memberid | book | clothes | both
> -------: | ---: | ------: | ---:
> 1 | 0 | 0 | 1
> 2 | 1 | 0 | 0
> 3 | 1 | 0 | 0
> 4 | 0 | 1 | 0
> 5 | 0 | 0 | 1
> 6 | 1 | 0 | 0
> 7 | 1 | 0 | 0

Answer 3

A table variable with hundreds of thousands of rows is going to be problematic for you.
If you check your query plan, you'll likely see that the optimizer expects that table variable to only contain one row.
Changing the structure to a local temp table, and perhaps adding an index to producttype, should significantly improve the performance of the query even before you optimize your code.
CREATE TABLE #TEST (memberid int, producttype varchar(7));
CREATE NONCLUSTERED INDEX tempTest ON #TEST(producttype);