MYSQL condition inside case not working - mysql

Question

I have two tables: Here is the
sqlfiddle (http://sqlfiddle.com/#!9/5a51734/5)
1) [table:data_aoc]
| aoc_id | aoc_name | aoc_type | client_id |
|------------------------------|-----------|
1 | MA01 | sensor_1 | 4 | 1 |
2 | MA02 | sensor_2 | 15 | 1 |
2) table:data_log
| log_id | log_aoc_id | trans_type | trans_value | trans_date |
|-------------------------------------------------------------|
1 | x1a1 | MA01 | 0 | 90 | 2017-10-20 |
2 | afaf | MA01 | 0 | 90 | 2017-10-21 |
3 | va12 | MA02 | 0 | 10 | 2017-10-21 |
4 | gag2 | MA02 | 0 | 10 | 2017-11-25 |
Expected Result
Total value for MA02 should be 10 but it shows 20
my queries as follows
SELECT
(CASE
WHEN a.aoc_type IN ('4')
THEN IFNULL((SUM(b.trans_value * case b.trans_type when '0' then -1 else 1 end)),0)
WHEN a.aoc_type IN ('15')
THEN IFNULL((SUM(b.trans_value * case when b.trans_type='0' AND DATE(b.trans_date) <= DATE(NOW()) then -1 else 1 end)),0)
END) as total
FROM data_aoc a
LEFT JOIN data_log b ON b.log_aoc_id = a.aoc_id
WHERE a.client_id='1'
GROUP BY a.aoc_name
ORDER BY a.aoc_id asc
Iam expecting when aoc_type is (15) it will sum the value within the date condition
DATE(b.trans_date) <= DATE(NOW())
but when i execute the queries, it produce result not within the date condition. *some timestamps are generated in advance beyond the NOW() date time.
The desired result should be:
| Total |
|-------|
| -180 |
| 10 |
But i get
| Total |
|-------|
| -180 |
| 0 | <----- it should be 10 because of the date condition i put
thank you!

Answer 1

As a follow-up of same findings from Don, And your clarification of don't count after, I came up with this query... Pre-check on the date first and if after, multiply by zero, OTHERWISE, apply the +/- 1 factor.
SELECT
SUM( b.trans_value *
CASE when ( a.aoc_type = '15'
AND b.trans_type = '0'
AND DATE(b.trans_date) > DATE(NOW()) )
then 0
when ( a.aoc_type = '4'
AND b.trans_type = '0' )
OR ( a.aoc_type = '15'
AND b.trans_type = '0'
AND DATE(b.trans_date) <= DATE(NOW()) )
then -1 else 1 end ) as total
FROM
data_aoc a
LEFT JOIN data_log b
ON a.aoc_id = b.log_aoc_id
WHERE
a.client_id='1'
GROUP BY
a.aoc_name
ORDER BY
a.aoc_id asc
Also posted on SQL Fiddle

Answer 2

It seems to be working exactly as it should.
With the date clause I get:
Sensor 1 = -180
Sensor 2 = 0
If you break down the summing you get two rows to be summed for sensor #2
10 on 10-21 (before the date restriction so it's multiplied by -1)
and
10 on 11-25 (after the date restriction so it's multiplied by 1)
10 * -1 + 10 * 1 = 0
The sensor #2 reading is correctly 0.
I do not understand why you think it should be anything else.