mysql count unique row values

Question

TABLE quotation

id  clientid
1   25
2   25
3   25
4   25
5   26

How can I query how many different clients exist in TABLE qu

Answer 1

I tried the following on a MySQL 5.x database.

id is an integer and clientid is an integer. I populated with two rows:

id  clientid
1   25
2   25

This SQL query will print the rows that have exactly 2 elements:

select * from test1 group by clientid having count(*) = 2;

If you want 2 or more elements, replace = 2 in the example above with >= 2.

select * from test1 group by clientid having count(*) >= 2;