John Stile select contiguous addresses that start on a bit boundary
Dec 17, 2015; 07:35
John Stile
select contiguous addresses that start on a bit boundary
I need help creating a select that returns 4 records that have contiguous addresses that start on a bit boundary.
If 4 do not exist, I need a return of zero records.
I would like to do this in one statement and I do not have ownership of this mysql server, so fancy views, temporary tables, indexing, etc are outside my permission level.
I am also not the only consumer of this database, so altering it for my needs could hurt the other consumers.
Below I specify the issue and where I am.
Thank you for your attention.
# # Create problem set # - This has non-contiguous addresses # - This has one status not 0 # - This has contiguous addresses that start before the bit boundary # CREATE TABLE addresses ( address BIGINT(20), status INT ); INSERT INTO addresses VALUES (100000000001,0), (100000000003,0), (100000000004,0), (100000000005,1), (100000000006,0), (100000000007,0), (100000000008,0), (100000000009,0), (100000000010,0), (100000000011,0), (100000000013,0), (100000000014,0), (100000000015,0), (100000000016,0), (100000000017,0); # # This shows the bit boundary, where the start is (address & 3) = 0 # select address, (address & 3) as boundary from addresses where address >0 and status=0 order by address limit 10 ; +--------------+----------+ | address | boundary | +--------------+----------+ | 100000000001 | 1 | | 100000000003 | 3 | | 100000000004 | 0 | | 100000000006 | 2 | | 100000000007 | 3 | | 100000000008 | 0 | | 100000000009 | 1 | | 100000000010 | 2 | | 100000000011 | 3 | | 100000000013 | 1 | +--------------+----------+ 10 rows in set (0.00 sec) # # This shows contiguous add, but they do not stat on the bit boundary # select c1.address, (address & 3) as boundary from addresses c1 where 4 = ( SELECT count(*) FROM addresses c2 WHERE c2.status = 0 and c2.address BETWEEN c1.address AND (c1.address + 3) ) limit 10;
I can't seem to add my ((address & 3) = 0) condition to the correct location to get the desired result. I don't understand how I can use c1.address in the BETWEEN, and yet I can't seem to make ((address & 3) = 0) work anywhere.
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Dec 17
John Stile Re: select contiguous addresses that start on a bit boundary
Dec 17, 2015; 08:14
John Stile
Re: select contiguous addresses that start on a bit boundary
Dec 17
John Stile Re: select contiguous addresses that start on a bit boundary
Dec 17, 2015; 14:10
John Stile
Re: select contiguous addresses that start on a bit boundary
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