how to do this query?

New to sql and may be a simple question for you:

I have four tables

sample:   sid, sname
make:     sid, mdate
measure:  sid, mdate, rid
result:   rid, resultdata

for a gaven sample it always has a sid and sname, but
it may or may not have any entries in the other
tables, the sample could be measured more than once
and each measure give a result row.
question:
how do I do a query that given a sid, it will retrieve
all the information available in the four tables, if
there are available. If, for example, all tables have
some entry for a gave sample it will retreve all the
information, if the "measure" and "result" are empty
for that sample it will give only the 'sample' and
'make' information....

please help

Thanks



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