Does anyone know any good resources on cardinality? I have three very similar tables involved in a big join and two of them have no cardinality on a certain column and are joining ver badly (no key taken at all!) but the other does have cardinality and is joining very well. This cardinality is the only aspect of the tables which is both different and something I don't fully understand. So I think that it must be this. Is there any way of forcing cardinality? Any help appreciated. Rob
Cardinality is a count of distinct object in any index.
If #index << #db, the index is selective.
If you make an index, you, may be, get the cardinality... I don't know any more...
see you.
p.s: # is for cardinality, as in math...
