I am trying to fetch the records from two tables.
1 - tokens 2 - transactions
In both tables there is same column user_id and tokens table has transaction_id. I am trying to get all transactions which has relation with token. I am trying following
select sum(`amount`) as aggregate
from `tokens`
where `user_id` in (15, 713, 49, 58, 60)
and exists
(select *
from `transactions`
where `tokens`.`transaction_id` = `transactions`.`id`
and (`custom` != 'BB' or `custom` is null)
)
When I change operator in my query like ``customis not null then I am getting the record, but not means query will show the record of 'BB'.
I have searched about it and found a good sentence from this thread
NULL Cannot be compared to any value using the comparison operators. NULL = NULL is false. Null is not a value. The IS operator is specially designed to handle NULL comparisons.
So in custom I have only one value which is BB and another is NULL.
My above query is not working.
Can someone kindly guide me how can I resolve the issue?
