<p>What's the simplest SQL statement that will return the duplicate values for a given column and the count of their occurrences in an Oracle database table?</p>

<p>For example: I have a <code>JOBS</code> table with the column <code>JOB_NUMBER</code>.  How can I find out if I have any duplicate <code>JOB_NUMBER</code>s, and how many times they're duplicated?</p>

Aggregate the column by COUNT, then use a HAVING clause to find values that appear greater than one time.
```
```
SELECT column_name, COUNT(column_name)
FROM table_name
GROUP BY column_name
HAVING COUNT(column_name) > 1;
```
```