How to find no of users in mysql table? - mysql

Question

I have table like below
A B C D
part1 p NA NA
part2 NA NA p
Part3 p p NA
I have to create table with part1 users,part2 users and part3 users. p represents users.
I have tried like below for part1 users but is giving all part1 and part2 and part3 users as 1.
SELECT count(distinct A) as no_of_part1_users
FROM table1
WHERE (A="part1" AND B="x") OR (A="part1" AND C="x") OR (A="part1" AND D="x");
I am getting output like below:
no_of_part1_users
1
I have applied same logic for part2 and part3 users but i am getting same output.
Desired output:
no_of_part1_users no_of_part2_users no_of_part3_users
1 1 2

Answer 1

To produce what you want, you could use a FROM-less SELECT with subqueries for each count. Each subquery uses a derived table that transforms the columns into rows using UNION ALL. Then this can be filtered and the count being taken.
SELECT (SELECT count(*)
FROM (SELECT b u
FROM table1
WHERE a = 'part1'
UNION ALL
...
UNION ALL
SELECT d u
FROM table1
WHERE a = 'part1') x
WHERE u <> 'NA') no_of_part1_users,
...
(SELECT count(*)
FROM (SELECT b u
FROM table1
WHERE a = 'part3'
UNION ALL
...
UNION ALL
SELECT d u
FROM table1
WHERE a = 'part3') x
WHERE u <> 'NA') no_of_part3_users;
But yeah, that's pretty ugly. Your design is really bad indeed. You should really fix that instead. Relational tables aren't spreadsheets!