Divide two counts giving an error

Question

I've a query in the following structure where im trying to divide in the select statement like this:
SELECT cnt1/ cnt2
FROM (SELECT count(*) cnt1, col1, col2
FROM emp),
(SELECT COUNT(*) cnt2, col1, col2
FROM all_tables);
How can i bring in additional fields from emp or all_tables (i.e col1 and col2)? I can get the divide calculation done but not able to get the other two fields in the main select statement as it gives me following error. These two columns col1 and col2 are there in both the tables.
00904. 00000 - "%s: invalid identifier"
Edited by: 1010059 on Jun 5, 2013 12:53 PM

Answer 1

Hi,
Welcome to the forum!
1010059 wrote:
I've a query in the following structure where im trying to divide in the select statement like this:
SELECT cnt1/ cnt2
FROM (SELECT count(*) cnt1, col1, col2
FROM emp),
(SELECT COUNT(*) cnt2, col1, col2
FROM all_tables);
How can i bring in additional fields from emp or all_tables (i.e col1 and col2)? I can get the divide calculation done but not able to get the other two fields in the main select statement as it gives me an error.How do you want to bring those columns in? I can't picture what the results would look like, or what you might want to achieve.
Whenever you have a problem, please post CREATE TABLE and INSERT statements for a little sample data, and the exact results you want from that data.
When you use an aggregate function, such as COUNT, the output of the query will contain 1 row for every group as defined by the GROUP BY clause. If there is no GROUP BY clause, the output will have 1 row.
You probably have hundreds of rows in all_tables, but even if you had only 2 or 3 rows, what would you want to display in the last 2 columns on the 1 row that the sub-query produces? The same goes for the sub-query on emp.
Take a few minutes to read the forum FAQ {message:id=9360002} It shows lots of ways to get better replies faster on this forum.