Dear all, I have a table "a" as the following: sql>select * from a; +------+------+ | x | y | +======+======+ | 1 | 1 | | 1 | 2 | | 1 | 3 | | 2 | 1 | | 2 | 2 | | 2 | 3 | | 2 | 1 | | 1 | 2 | | 2 | 3 | +------+------+ 9 tuples I want to count the number of distinct tuples in the table, so I did the following: sql>select count(*) from (select distinct x,y from a) as b; +------+ | L17 | +======+ | 2 | +------+ 1 tuple sql>select count(x) from (select distinct x,y from a) as b; +------+ | L20 | +======+ | 2 | +------+ 1 tuple sql>select count(y) from (select distinct x,y from a) as b; +------+ | L21 | +======+ | 3 | +------+ 1 tuple It looks like that count() automatically counts the distinct values of x and y, while "select distinct x,y from b" does give me what I want: sql>select distinct x, y from b; +------+------+ | x | y | +======+======+ | 1 | 1 | | 1 | 2 | | 1 | 3 | | 2 | 1 | | 2 | 2 | | 2 | 3 | +------+------+ 6 tuples Is this an expected behaviour of count()? If yes, how can I get the #tuples of "select distinct x,y from b"? Thanks in advance! Jennie PS> info about mserver5: $ mserver5 # MonetDB server v5.18.6, based on kernel v1.36.6 # Serving database 'demo', using 4 threads # Compiled for x86_64-unknown-linux-gnu/64bit with 64bit OIDs dynamically linked # Found 7.751 GiB available main-memory. # Copyright (c) 1993-July 2008 CWI. # Copyright (c) August 2008-2010 MonetDB B.V., all rights reserved # Visit http://monetdb.cwi.nl/ for further information #warning: please don't forget to set your vault key! #(see [prefix]/stable/debug/etc/monetdb5.conf) # Listening for connection requests on mapi:monetdb://127.0.0.1:50000/
include sql; # MonetDB/SQL module v2.36.6 loaded