SQL - Get count of phone calls that resulted in meeting - mysql

Question

I have a table named 'reports', something like this:
id
user_id
type
customer_id
text
created_at
1
1
1
3
....
2021-08-07 17:00:52
2
1
1
3
....
2021-08-12 10:11:11
3
1
1
9
....
2021-08-12 10:08:14
4
1
2
3
....
2021-08-12 10:04:08
5
1
2
9
....
2021-08-13 20:32:21
6
2
1
7
....
2021-08-13 20:34:17
7
2
2
8
....
2021-08-14 18:55:09
I want to get the count of rows that a user has submitted type 1 reports that result in a type 2 report.
Type 1 report means reporting a phone call to the customer and type 2 means meeting the customer. I want to receive the number of calls that resulted in an meeting.
For example, for user 1 should returns 3, because for customer 3, IDs 1 and 2 have led to ID 4, and for customer 9, ID 3 has led to ID 5.
But for user 2, ID 7 is type 2 but there is no previous type 1 report for customer 8, so it returns 0.

Answer 1

Schema (MySQL v5.7)
CREATE TABLE reports
(id int auto_increment primary key,
user_id int,
type int,
customer_id int,
text varchar(4),
created_at varchar(19)
);
INSERT INTO reports
(id, user_id, type, customer_id, text, created_at)
VALUES
(1, 1, 1, 3, '....', '2021-08-07 17:00:52'),
(2, 1, 1, 3, '....', '2021-08-12 10:11:11'),
(3, 1, 1, 9, '....', '2021-08-12 10:08:14'),
(4, 1, 2, 3, '....', '2021-08-12 10:04:08'),
(5, 1, 2, 9, '....', '2021-08-13 20:32:21'),
(6, 2, 1, 7, '....', '2021-08-13 20:34:17'),
(7, 2, 2, 8, '....', '2021-08-14 18:55:09');
Query #1
SELECT x.user_id
, COUNT(DISTINCT y.id) total
FROM reports x
LEFT
JOIN reports y
ON y.id<=x.id
AND y.user_id = x.user_id
AND y.customer_id = x.customer_id
AND y.type = 1
WHERE x.type = 2
GROUP
BY x.user_id;
user_id
total
1
3
2
0
View on DB Fiddle

Answer 2

You haven't shown how your are expecting results, but simply refer to User 1 and 2 and the total votes, you can try using a lateral join
select user_id, Coalesce(Sum(valid),0) rowcount
from reports r
join lateral (
select
case when exists (select * from reports rr
where rr.user_id=r.user_Id and rr.type=2 and rr.customer_id=r.customer_Id and r.type=1)
then 1 end valid
)x
group by User_Id
Example Fiddle

Answer 3

First you Count the number of customers that comply with your criterioa type and typoe 2. But ti get all user you need to join the list of users
I used LEFT join as also RIGHt JOIN in my example
CREATE TABLE reports
(`id` int, `user_id` int, `type` int, `customer_id` int, `text` varchar(4), `created_at` varchar(19))
;
INSERT INTO reports
(`id`, `user_id`, `type`, `customer_id`, `text`, `created_at`)
VALUES
(1, 1, 1, 3, '....', '2021-08-07 17:00:52'),
(2, 1, 1, 3, '....', '2021-08-12 10:11:11'),
(3, 1, 1, 9, '....', '2021-08-12 10:08:14'),
(4, 1, 2, 3, '....', '2021-08-12 10:04:08'),
(5, 1, 2, 9, '....', '2021-08-13 20:32:21'),
(6, 2, 1, 7, '....', '2021-08-13 20:34:17'),
(7, 2, 2, 8, '....', '2021-08-14 18:55:09')
;
SELECT IFNULL(Counts,0),t1.user_id
FROM (SELECT COUNT(distinct r.customer_id) counts,user_id
FROM reports r
WHERE type = 1 AND EXISTS(SELECT 1 FROM reports WHERE type = 2 AND customer_id = r.customer_id)
GROUP BY user_id) r RIGHT JOIN (SELECT DISTINCT user_id FROm reports) t1 ON r.user_id = t1.user_id
IFNULL(Counts,0) | user_id
---------------: | ------:
2 | 1
0 | 2
SELECT IFNULL(Counts,0),t1.user_id
FROM (SELECT DISTINCT user_id FROm reports) t1 LEFT JOIN (SELECT COUNT(distinct r.customer_id) counts,user_id
FROM reports r
WHERE type = 1 AND EXISTS(SELECT 1 FROM reports WHERE type = 2 AND customer_id = r.customer_id)
GROUP BY user_id) r ON r.user_id = t1.user_id
IFNULL(Counts,0) | user_id
---------------: | ------:
2 | 1
0 | 2
db<>fiddle here