how to count column values?

Question

Here's my query:

SELECT DISTINCT r1.STATE_OFFICE_CODE,
   r1.AREA_OFFICE_CODE,
   r1.AREA_OFFICE_NAME,
   r2.LAST_EOD_EXECUTION
FROM report_one r1
INNER JOIN report2 r2 ON r1.distributor_code = r2.distributor_code
ORDER BY r1.AREA_OFFICE_CODE;

It's working fine. Output:

But when I try to count the columns of r2.LAST_EOD_EXECUTION I get error "not a single group by function":

SELECT DISTINCT r1.STATE_OFFICE_CODE,
   r1.AREA_OFFICE_CODE,
   r1.AREA_OFFICE_NAME,
   r2.LAST_EOD_EXECUTION,
   count(r2.LAST_EOD_EXECUTION) AS NumberOfDates
FROM report_one r1
INNER JOIN report2 r2 ON r1.distributor_code = r2.distributor_code
ORDER BY r1.AREA_OFFICE_CODE;

Please can anyone help? How can I count the values?

Answer 1

Drop the distinct keyword and add a group by clause:

SELECT r1.STATE_OFFICE_CODE,
   r1.AREA_OFFICE_CODE,
   r1.AREA_OFFICE_NAME,
   r2.LAST_EOD_EXECUTION,
   count(r2.LAST_EOD_EXECUTION) AS NumberOfDates
FROM report_one r1
INNER JOIN report2 r2 ON r1.distributor_code = r2.distributor_code
GROUP BY r1.STATE_OFFICE_CODE,
   r1.AREA_OFFICE_CODE,
   r1.AREA_OFFICE_NAME,
   r2.LAST_EOD_EXECUTION
ORDER BY r1.AREA_OFFICE_CODE;

EDIT:
It's not completely clear what you're trying to achieve, but if you're trying to get the number of distinct LAST_EOD_EXECUTION values per group, you'd need to use the distinct keyword inside the count :

SELECT r1.STATE_OFFICE_CODE,
   r1.AREA_OFFICE_CODE,
   r1.AREA_OFFICE_NAME,
   r2.LAST_EOD_EXECUTION,
   count(distinct r2.LAST_EOD_EXECUTION) AS NumberOfDates
FROM report_one r1
INNER JOIN report2 r2 ON r1.distributor_code = r2.distributor_code
GROUP BY r1.STATE_OFFICE_CODE,
   r1.AREA_OFFICE_CODE,
   r1.AREA_OFFICE_NAME,
   r2.LAST_EOD_EXECUTION
ORDER BY r1.AREA_OFFICE_CODE;