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Posted by Robert Klemme on 09/20/06 13:36
On 20.09.2006 10:51, yicong wrote:
> I want to select one field from a table,but it should on some conditions
> which refer to 5 table ,such as A.FILED1=B.FIELD1 AND B.FIELD2=C.FIELD3 AND
> ...
> Should I use case "select sum(a.amount) from a,b,c,... where
> a.field1=b.field1 and b.field2=c.field2 and ..." or "select sum(a.amount)
> from select b.field1 from select c.field2 from...."?And which case is more
> efficiency?
I cannot make much sense of this. Please rephrase your question and
especially provide more detail (DDL, DML).
A general remark: if you have two equivalent DML statements you can
easily check with MS tools (Profiler, Query Analyzer) which of the two
is more efficient.
Regards
robert
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