SQL Query to select one set when there are duplicates

Question

SELECT REF_ID, MIN(SLA) FROM [SLA] WHERE [FIRST_DATE] > '2016-09-30' GROUP BY  [REF_ID]  

This will list the items with minimum SLA when there are duplicates

REF_ID    |    COUNT  
11    |    1  
12    |    1  
13    |    1  
14    |    2  

I would like to get the count of SLAs, Can someone provide a query for this please.

SLA    |    COUNT  
1    |    3  
2    |    1  
0    |    0  

Thanks

Answer 1

To get the number of SLAs:

select SLA, count(SLA) from table group by SLA