Dear Team,
I hope this message finds you well.
I’m encountering an issue with the UNION ALL
operation in MySQL. Specifically, it behaves like a regular UNION
by removing duplicate rows instead of preserving them. Here’s what I’ve observed:
- When I attempt to
UNION ALL
two empty rows, the result only shows a single row. - Similarly, if I try to add two rows with the same values, the second row gets removed.
According to MySQL behavior, UNION ALL
should retain duplicate rows, so we must be able to create duplicate rows using it.
Key Observations:
- In Holistics Model View: The query works correctly, and the duplicates are preserved.
- In Exports or Reports Tab: Duplicates are removed, even when exporting to Excel.
Attached are images for clarity on the issue.
Could you please investigate why UNION ALL
behaves differently in these cases? Most importantly, ensuring that duplicates are preserved when exporting data or viewing it in the Reports Tab would be critical for accuracy.
Thank you for your attention to this matter.
Best regards,
Hamza