Getting count of distinct values

Question

resulttable:

+-------------+-----------+
| resultSetID | projectID |
+-------------+-----------+
|           1 |         1 |
|           1 |         2 |
|           1 |         3 |
|           2 |         1 |
|           2 |         2 |
|           3 |         1 |
|           3 |         2 |
|           3 |         3 |
+-------------+-----------+

Query:

SELECT
    COUNT( projectID ) 
FROM
    resulttable
WHERE
    projectID = 3

... correctly returns 2. However, I want the counts of each ID without using the WHERE condition, how do I do that?

Answer 1

Do you just want group by ?

SELECT projectId, COUNT( * ) 
FROM resulttable
GROUP BY projectID;

Answer 2

The following query is used to get all the data for the projectId but if you want to get a specific query data without where you can use having instead

SELECT projectId, COUNT( * ) 
FROM resulttable
GROUP BY projectId having projectId = 3;

Answer 3

The following query should work for you:

SELECT projectID, SUM(resultSetID) 
FROM resulttable
GROUP BY projectID;