Re: Partial key

[noudshoorn]

I explain it to you:

the key is a multiple index on name, departuredate and departuretime.
the name of the key is name (this doesn't seem the problem).
the tablename is A.
the table has now 12 rows.
10 rows with name starting with an N:
Noordman
Noorman
Noorman
Naarman
Noordman
Noordman
Noorman
Naarman
Noorman
Noordman.

Explain select * form A where name like 'N'%' says that the possible key is name, but it doesn't use the index. In the execution of the select the rows are showed in the range they were inserted.

But when I execute the select * from A where name like 'Noordm%' then the selected rows are displayed conform the index. You can see that because date and time are also in the correct range.

I did several tests and I see that the index only is used when the complete names selected by LIKE are the same and the number of selected rows is <= the total numer of rows.

What I want is that in all cases the index is used.

Any ideas,

Nico Oudshoorn