How to use min() and max() in an efficient way? - sql

Question

I have an sql query where I check if a value is between a max and a min value of a table. I've now implement this as follows:
SELECT spectrum_id, feature_table_id
FROM 'spectrum', 'feature'
WHERE `spectrum`.msrun_msrun_id = 1
AND `feature`.msrun_msrun_id = 1
AND (SELECT min(rt) FROM `convexhull` WHERE `convexhull`.feature_feature_table_id = `feature`.feature_table_id) <= scan_start_time
AND scan_start_time <= (SELECT max(rt) FROM `convexhull` WHERE 'convexhull'.feature_feature_table_id = 'feature'.feature_table_id)
AND (SELECT min(mz) FROM `convexhull` WHERE `convexhull`.feature_feature_table_id = `feature`.feature_table_id) <= base_peak_mz
AND base_peak_mz <= (SELECT max(mz) FROM `convexhull` WHERE `convexhull`.feature_feature_table_id = `feature`feature_table_id)
This is running very slowly, because I'm selecting from convexhull 4 times every time I run this query, so I tried to improve it using an inner join:
SELECT spectrum_id, feature_table_id
FROM 'spectrum', 'feature'
INNER JOIN `convexhull` ON `convexhull`.feature_feature_table_id = `feature`.feature_table_id
WHERE `spectrum`.msrun_msrun_id = ? "+
AND `feature`.msrun_msrun_id = ? "+
AND min(`convexhull`.rt) <= scan_start_time "+
AND scan_start_time <= max(`convexhull`.rt) "+
AND min(`convexhull`.mz) <= base_peak_mz "+
AND base_peak_mz <= max(`convexhull`.mz)", spectrumFeature_InputValues)
However, the min() and max() statements can only be used after a select statement. How can I make the first query more efficient, so that I can get the min and max rt and mz without having to do 4 queries?

Answer 1

EDIT: had a few more mins and looked again and realised all the data comes from that one table so something like this should work
SELECT
spectrum_id
,feature_table_id
FROM
spectrum AS s
INNER JOIN feature AS f
on f.msrun_msrun_id = s.msrun_msrun_id
INNER JOIN (select
feature_feature_table_id
,min(rt) AS rtMin
,max(rt) AS rtMax
,min(mz) AS mzMin
,max(mz) as mzMax
FROM
convexhull
GROUP BY
feature_feature_table_id
) AS t
ON t.feature_feature_table_id = f.feature_table_id
WHERE
s.msrun_msrun_id = 1
AND s.scan_start_time >= t.rtMin
AND s.scan_start_time <= t.rtMax
AND base_peak_mz >= t.mxMin
AND base_peak_mz <= t.mzMax
I think you want to select from the convexhull table and group by feature_feature_table_id getting the min and max rt within that grouping.
you can then wrap that select in brackets give it a name (as t) and join to it.
Hope this is enought to get you on the road.. if not create a sample schema here: http://sqlfiddle.com/
and put in your query and i can modify it.
as a side note, I think you wan to join these tables on a particular field rather than select from both with a where clause compare:
SELECT spectrum_id, feature_table_id
FROM 'spectrum', 'feature'
WHERE `spectrum`.msrun_msrun_id = 1
AND `feature`.msrun_msrun_id = 1
and:
SELECT
spectrum_id
,feature_table_id
FROM
spectrum AS s
INNER JOIN feature AS f
on f.msrun_msrun_id = s.msrun_msrun_id
WHERE
s.msrun_msrun_id = 1
If i have got something wrong there let me know.