selecting from mysql table using an expression - mysql

Question

I'm using Mysql and I'm stuck on what I hope is a simple problem.
I need to select data from a table if one condition is true or another condition is true.
One select I tried returns data, but a lot more data than it should. Indeed the table contains just 66 records however my query is returning 177 records. I'm misunderstanding something.
I need to select data if ['city' is equal to a value and 'type' is golden] or 'type' is within a category called 'charms'
I've tried this query
SELECT b.*
FROM bubbles b, bubble_types bt
WHERE
b.city = 10
AND b.type = 'golden'
OR bt.category = 'charm'
AND bt.type = b.type;
and this one (which doesn't work at all but may be closer to the mark?)
SELECT b.*
IF(b.city = 10, b.type = 'golden'),
IF(bt.category = 'charm', bt.type = b.type)
FROM bubbles b, bubble_types bt;
Hopefully what I want makes sense?
I should get about 10 rows from the 66 of those bubbles in city 10 that are 'golden', or those bubbles whose type field puts them in category 'charm'.
Thanks;
edit sample table data for bubble_types:
+----+----------+------------+
| id | category | type |
+----+----------+------------+
| 1 | bubble | golden |
| 2 | charm | teleport |
| 3 | charm | blow |
| 4 | badge | reuser |
| 5 | badge | winner |
| 6 | badge | loothunter |
| 7 | charm | freeze |
| 8 | badge | reuser |
| 9 | badge | winner |
| 10 | badge | loothunter |
+----+----------+------------+
mysql> describe bubbles;
+-------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+---------------------+------+-----+---------+----------------+
| id | bigint(20) unsigned | NO | PRI | NULL | auto_increment |
| city | bigint(20) | YES | | NULL | |
| type | varchar(32) | YES | | NULL | |
| taken_by | bigint(20) | YES | | NULL | |
| taken_time | bigint(20) | YES | | NULL | |
| label | varchar(256) | YES | | NULL | |
| description | varchar(16384) | YES | | NULL | |
| created | datetime | YES | | NULL | |
+-------------+---------------------+------+-----+---------+----------------+

Answer 1

You are so close! Take the "WHERE"-ness of your first go with the parenthesis of your second (and add an appropriate ON clause to your JOIN):
SELECT b.*
FROM bubbles b
JOIN bubble_types bt
ON b.type = bt.type
WHERE
(b.city = 10 AND b.type = 'golden')
OR
(bt.category = 'charm' AND bt.type = b.type);
The devil is in the details of associativity of AND and OR in the where clauses. When in doubt, use parenthesis to make your intentions explicit.