I am trying to get sum of the amount on distinct ext_id.
| Id | Ext_id | amount | 
|---|---|---|
| 1 | 234 | 5 | 
| 2 | 234 | 5 | 
| 3 | 235 | 10 | 
| 4 | 236 | 8 | 
| 5 | 236 | 8 | 
Select SUM(amount) from Table1 -- this will get me sum of all  => 36
I want just sum of distinct Ext_id which should be 23. Can someone help me with this? THanks in advance!
 
    