Assistance with MySQL Query - Omitting, Grouping? - mysql

Question

Doing a bit of investigation and writing a query against a logs db.
I've joined a number of tables to bring back the data that I need, but i'd like to clean it up a bit.
The query returns all the users and which features they have enabled on their account.
Here is what i'm trying to do to clean it up:
Their is a column called 'actions' which has two states, 'added' and 'removed'
If a user feature has an action of 'removed' then I want to not show any of the rows for the same feature for that user which are also marked as 'added'
Is this possible?!
Here is what I have so far:
select users.id as site_id, users.company_name, feature_log.featurecode, feature.minimum_account as feature_type, users.account_type as site_type, account_types.name as account, feature_log.action, feature_log.time
from users
inner join
feature_log
on users.id = feature_log.siteid
inner join
feature
on feature_log.featurecode = feature.featurecode
inner join account_types
on users.account_type_INC = account_types.id
where feature.minimum_account != 0
AND feature.minimum_account > users.account_type
AND users.status = 'Y'
ORDER BY feature_log.time DESC
Thanks for any support!

Answer 1

So, in order to "mute" all the features, that have been "removed" at any point in time for a given user, you can add a (left) join on the following subquery:
SELECT DISTINCT users.id as siteid, feature_log.featurecode, TRUE as mute_feature
FROM users
INNER JOIN feature_log ON (users.id = feature_log.siteid)
WHERE action = 'removed'
This will be the list of features that a given user disabled at some point in time. Then in your query's WHERE clause, you'd add a filter like so:
AND NOT IFNULL(mute_feature, FALSE)
Essentially, that'd bring your whole query to be:
select users.id as site_id, users.company_name, feature_log.featurecode, feature.minimum_account as feature_type, users.account_type as site_type, account_types.name as account, feature_log.action, feature_log.time
from users
inner join
feature_log
on users.id = feature_log.siteid
left join (
SELECT DISTINCT users.id as siteid, feature_log.featurecode, TRUE as mute_feature
FROM users
INNER JOIN feature_log ON (users.id = feature_log.siteid)
WHERE action = 'removed'
) as muted_features ON (feature_log.siteid = muted_features.siteid AND feature_log.featurecode = muted_features.featurecode)
inner join
feature
on feature_log.featurecode = feature.featurecode
inner join account_types
on users.account_type_INC = account_types.id
where feature.minimum_account != 0
AND feature.minimum_account > users.account_type
AND users.status = 'Y'
AND NOT IFNULL(mute_feature, FALSE)
ORDER BY feature_log.time DESC