Re: Query with GROUP BY not using Index

[Øystein Grøvlen]

Hi,

Yes, GROUP BY will implicitly order on the GROUP BY columns.

I think your query could be simplified as follows:

SELECT t1.wafer_name, MIN(t1.date) FROM epi_flash_meas t1 JOIN epi_wafer t2 USING (wafer_name) GROUP BY wafer_name ORDER BY t1.date DESC LIMIT 0,30;

Øystein Grøvlen,
Senior Principal Software Engineer,
MySQL Group, Oracle,
Trondheim, Norway