Cannot produce query to find multiple under same member record
I have the following sample table:
ID | Code
=================
1 | 123
2 | 123
2 | 456
2 | 456
2 | 789
3 | 123
3 | 789
I want to return the ID and code in which the same code appears for a single ID.
The results for the desired query based on the table above would be:
ID | Code
==============
2 | 456
as code 456 appears twice for ID 2.
The query I have been using (which is not returning the desired results is:
select id, code from table gro开发者_如何学编程up by code having count(code) > 1;
Note: the query above would return 456 and 789 as they both appear more than once but I only want it to show records for multiple appearances for a single ID.
need to group by both columns
SELECT id, code
FROM table
GROUP BY id, code
HAVING COUNT(code) > 1;
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