Need Help With Simple MySQL SELECT - mysql

Question

I've got a table of crime data. In a simplified version, it would look like this:
Table Headings:
crime_id, neighborhood, offense
Table Data:
- 1, Old Town, robbery
- 2, Bad Town, theft
- 3, Bad Town, theft
- 4, Uptown, stolen auto
If I SELECT * FROM mytable WHERE offense ='theft', then the results for Bad Town are returned. But, I'm making a ranking, so what I'm really interested in is:
Old Town: 0
Bad Town: theft
Bad Town: theft
Uptown: 0
How do I write a SELECT statement that returns cases where there are thefts, but also returns neighborhoods that don't have an entry for the specified offense?
UPDATE: This my actual SELECT. I'm having problems applying the solution that p.campbell and Gratzy were so kind to post to this SELECT. How do I apply the CASE statement with the COUNT(*)?
SELECT
cbn.neighborhoods AS neighborhoods,
COUNT(*) AS offenses,
TRUNCATE(((na.neighborhood_area_in_sq_meters /1000) * 0.000386102159),2) AS sq_miles,
( COUNT(*) / ((na.neighborhood_area_in_sq_meters /1000) * 0.000386102159) ) AS offenses_per_sq_mile
FROM
wp_crime_by_neighborhood cbn, wp_neighborhood_area na
WHERE
cbn.offense='theft'
AND
cbn.neighborhoods = na.neighborhoods
GROUP BY
cbn.neighborhoods
ORDER BY
offenses_per_sq_mile DESC

Answer 1

If you're looking to make a ranking, wouldn't it be better to get the number of thefts in Bad Town rather than a row for each? Something like this:
select distinct mt.neighborhood, ifnull(total, 0)
from mytable mt
left join (
select neighborhood, count(*) as total
from mytable
where offense = 'theft'
group by neighborhood
) as t on t.neighborhood = mt.neighborhood
Based on the data you gave, this query should return:
Old Town: 0
Bad Town: 2
Uptown: 0
That seems more useful to me for making a ranking. You can easily throw an order by on there.

Answer 2

I would think using a case statement should do it.
http://dev.mysql.com/doc/refman/5.0/en/case-statement.html
something like
Select neighborhood,
case offense when 'theft' then offense else '0' end case
from table

Answer 3

Try this:
SELECT cbn.neighborhoods AS neighborhoods,
CASE WHEN IFNULL(COUNT(*),0) > 0 THEN CONCAT(COUNT(*), ' ', offense)
ELSE '0'
END AS offenses
--- ... and the rest of your query
FROM wp_crime_by_neighborhood cbn
INNER JOIN wp_neighborhood_area na
ON cbn.neighborhoods = na.neighborhoods
WHERE cbn.offense='theft'
GROUP BY cbn.neighborhoods
--ORDER BY offenses_per_sq_mile DESC