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One of JEHOVAH's Witnesses (TV)

Seasoned MySQL DBA (SCMDBA) since 2007-08-11

Profile for RolandoMySQLDBA on Stack Exchange, a network of free, community-driven Q&A sites


Apr
11
reviewed Approve suggested edit on DB2 PureScale on Linux
Apr
11
reviewed Approve suggested edit on System Preferences quits unexpectedly due to MySQL plug-in
Apr
10
reviewed Reject suggested edit on How to speed up queries on a large 220 million rows table (9 gig data)?
Apr
10
comment Delete the N oldest entries grouped by multiple columns
Another advantage to my solution is that the DELETE is simplifed by using a JOIN and interation to produce a simple DELETE FROM words WHERE id IN (...);. This is safer that doing a DELETE JOIN of a table against itself because the MySQL Query Optimizer likes to play smoke and mirrors with data that can result in possibly seeing incomplete DELETEs : See dba.stackexchange.com/a/1384/877 .
Apr
9
comment Delete the N oldest entries grouped by multiple columns
The way I solved this involves user-defined variables and very careful iterative programming. Most people forget that SQL is a declarative programming language. I just increment the variables on each row and do IFs when necessary. Convoluted as it may seem, it works !!!
Apr
9
reviewed No Action Needed Mysql: order by field or select union?
Apr
9
revised Delete the N oldest entries grouped by multiple columns
added 54 characters in body
Apr
9
reviewed Approve suggested edit on mySql Relationships / Index - Checking for duplicates
Apr
9
comment Delete the N oldest entries grouped by multiple columns
OMG I actually solved it. Please look it over !!!
Apr
9
revised Delete the N oldest entries grouped by multiple columns
added 4043 characters in body
Apr
9
comment Delete the N oldest entries grouped by multiple columns
I am confused now. I thought the question was to delete everything but the last two rows per word and category. As my DELETE query shows, the two rows you specified should be deleted were deleted as the question suggested.
Apr
9
comment Delete the N oldest entries grouped by multiple columns
Did my answer solve your problem ???
Apr
9
reviewed Close How to install SQL Server 2008 R2 Profiler
Apr
9
answered When and why can this kind of deadlock occur?
Apr
9
revised MySQL slave stuck in “Reading event from the relay log”?
added 573 characters in body
Apr
9
reviewed Approve suggested edit on POSTGRES DB Server Blunder
Apr
9
comment Changing TEXT to VARCHAR
Text fields do not get considered part of the Row Length Limits. Switching to VARCHAR/CHAR may needlessly impose such a limitation and introduce new problems (ibdata1 growth, frequent transaction checkpointing, and so forth). OK, in simple English, changing to VARCHAR will not help.
Apr
9
revised Changing TEXT to VARCHAR
added 182 characters in body
Apr
9
answered Changing TEXT to VARCHAR
Apr
9
revised Changing TEXT to VARCHAR
edited tags