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Subject: Re: [regrep] Inner joins using Entry level SQL-1992
Richard Martell wrote: > Diego Ballve wrote: > >> Hi Richard, >> >> What experience has shown is that we need a LEFT JOIN for some cases, >> for instance you have this kind of parameterized query: >> >> SELECT * FROM RegistryObject ro, Name_ nm, Description d >> WHERE nm.parent = ro.id AND '$name' = nm.value >> AND d.parent = ro.id AND '$desc' = d.value >> >> Now, since name and description are not mandatory, any RO that does >> not have name/desc will be cut out of that result set. Imagine that >> you want to search with $name = 'MyObject' and $desc = '%'. You won't >> get all objects named 'MyObject', but only the ones that have any >> description. >> >> This would return also objects without name/desc: >> >> SELECT * FROM RegistryObject ro >> LEFT JOIN Name_ nm ON nm.parent = ro.id >> LEFT JOIN Description d ON d.parent = ro.id >> WHERE '$name' = nm.value AND '$desc' = d.value >> >> Regards, >> Diego >> > > Then this would definitely call for an "upgrade" to Intermediate SQL > if this were to be acceptable as a naked SQL query (vs. generated from > some filter query--is this possible?). Most--if not all--commercial > and leading open source relational databases will handle such queries > these > days, so it doesn't really pose a technical hurdle. Or the implementer > does some pre-processing to make it palatable. If the backend chokes, > just throw up an exception. > > I would consider this a minor enhancement. Perhaps Diego can submit > this comment ;-) > > +1 Diego and I can work offline to get the comment submitted. Thanks. -- Regards, Farrukh
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