> The select(min) and select(max) took as long as the table scan to find
> the count. It seems logical if a btree type index is available (such
> as pk_cnx_ds_sis_bill_detl_tb) where the most significant bit of the
> index is the column requested, it should be little more than a seek
> first or seek last in the btree. Obviously, it won't work with a hashed
> index (which is neither here nor there).
In the meantime you can use:
select extr_stu_id from cnx_ds_sis_bill_detl_tb order by 1 desc limit 1; -- max
select extr_stu_id from cnx_ds_sis_bill_detl_tb order by 1 asc limit 1; -- min
I guess that is the reason why nobody felt really motivated to implement
this optimization. Besides these statements are more powerful, since they can fetch
other columns from this min/max row. The down side is, that this syntax varies across
db vendors, but most (all?) have a corresponding feature nowadays.
select first 1
select top 1 ...
This is actually becoming a FAQ :-)
Andreas