return max value from column [modified]
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hello, does anybody know how to write a query that returns the maximum value of a column? here is what i have so far:
SELECT barcode, wellname, well.ph, proteinname, score, time FROM well INNER JOIN welldrop ON well.wellkey=welldrop.wellkey INNER JOIN imageset ON welldrop.dropkey=imageset.dropkey WHERE well.barcode=1111this query returns several rows for each "wellkey". i only want to return one row for each wellkey, with the most recent date (found in the time field of the imageset table). i tried using MAX(time), but i got an error... thanks! RC -- modified at 17:20 Wednesday 28th June, 2006 -
hello, does anybody know how to write a query that returns the maximum value of a column? here is what i have so far:
SELECT barcode, wellname, well.ph, proteinname, score, time FROM well INNER JOIN welldrop ON well.wellkey=welldrop.wellkey INNER JOIN imageset ON welldrop.dropkey=imageset.dropkey WHERE well.barcode=1111this query returns several rows for each "wellkey". i only want to return one row for each wellkey, with the most recent date (found in the time field of the imageset table). i tried using MAX(time), but i got an error... thanks! RC -- modified at 17:20 Wednesday 28th June, 2006i think i figured it out. the following serves my purposes: SELECT barcode, wellname, well.ph, proteinname, score, MAX(time) AS time FROM well INNER JOIN welldrop ON well.wellkey=welldrop.wellkey INNER JOIN imageset ON welldrop.dropkey=imageset.dropkey WHERE well.barcode=1111 GROUP BY barcode,wellname