Re: [GENERAL] group by of multi columns

Thank you, this works like a charm. On 2015年1月4日周日 20:01 Andreas Kretschmer wrote: > Flyingfox Lee wrote: > > > I am doing a `group by` on a table with ~ 3 million rows, the code is > simply > > `select A, B, C, D,E count(1) from t group by A, B, C, D, E order by &g

[GENERAL] group by of multi columns

I am doing a `group by` on a table with ~ 3 million rows, the code is simply `select A, B, C, D,E count(1) from t group by A, B, C, D, E order by 6`, it takes ~ 3 minutes for this operation and there are ~ 500 rows returned. So, to speed this up, should I add a composite index on A, B, C, D, E or