On a second thought, you probably would want to group the R4 sub-query
only by reading_date and loc_code, join it to R1 by the same two
columns, and leave instrument_name and reading_time completely out of
the R4 sub-query. That is, if I understood what you're after here.
-Pasi
--
Pasi Jouhikainen 24h Phone: +358-40-7310859
jouhikai_at_cc.helsinki.fi 24h Fax: +358-42-7310859
Address: Ylisrinne 1 As 33 / 02210 Espoo / Finland
or: 351 2nd Ave Pl, #4 / Coralville, IA 52241 / USA
Received on Sun Feb 20 2000 - 17:21:24 CST
