datetime vs date,time

[Alberto González]

Hello i wrote this in other forum inside mysql forums:

I have a table with ~1500000 records with two columns date,time.

I thought change two columns to one as datetime.

I created a tables and i saw the difference:

date,time it's 0,20 secs fastest than datetime with ~1500000

i used select benchmark(10000000,(select count(*) from tbl1 order by field desc));

1 row in set (6.93 sec)

and select benchmark(10000000,(select count(*) from tbl2 order by field1,field2 desc));
1 row in set (6.76 sec)