On Dec 11, 2008, at 12:44 PM, David Avendasora wrote:
Hi all,
I've googled this, but can't seem to find any answers even though
I'm guessing it's a pretty common thing.
I have a table that has nearly 2 million rows and I want to retrieve
the maximum value used in the entire table for a given field. The
SQL equivelent would be:
SELECT MAX(FIELD) FROM TABLE
Ideally, I'd like the whole row like this would get for me:
SELECT * FROM TABLE
WHERE ID = (SELECT MAX(ID) FROM TABLE)
but I'd be happy just to get the maximum value in that one field.
Should I just do it with straight SQL, or is there a good EOF/Wonder
way to do it where I let EOF deal with the DB?
The field is indexed, so the straight SQL call is instantaneous.
Dave, Dave, Dave...
If it was me, I'd use this cool tool that I have. I think it is
called a computer. You might want to get one. I hear these ones from
Apple are very nice. Then, I'd search ERExtensions/Sources for
"max", all case insensitive like. Who knows what I might find?
/**
* Computes an aggregate function for a given attribute
* restricted by a given qualifier. For instance
* select MAX(AGE) from User where name like 'M*'
*
* @param ec editing context used for the fetch
* @param entityName name of the entity
* @param attributeName attribute for the function to be
performed on
* @param function name, ie MAX, MIN, AVG, etc.
*
* @return aggregate result of the fuction call
*/
public static Number
aggregateFunctionWithQualifier(EOEditingContext ec,
String
entityName,
String
attributeName,
String
function,
String
fetchSpecificationName,
NSDictionary
bindings) {
Chuck
--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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