Question

I’m trying to count the number of rows that have distinct values in both of the columns “a” and “b” in my Sybase ISQL 9 database.

What I means is, the following dataset will produce the answer “4”:

a b

1 9

2 9

3 8

3 7

2 9

3 7

Something like the following syntax would be nice:

SELECT COUNT(DISTINCT a, b) FROM MyTable

But this doesn’t work.

I do have a solution:

SELECT COUNT(*) FROM
  (SELECT a, b 
     FROM MyTable 
    WHERE c = 'foo'
    GROUP BY a, b) SubTable

But I was wondering if there is a neater way of constructing this query?

Answer 1

You could concatenate a and b together into 1 string like this (TSQL, hopefully something very similar in Sybase:

SELECT COUNT(DISTINCT(STR(a) + ',' + STR(b)))
FROM @YourTable