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     1  +1 2014 jul 29seco back up reviewsA review of SecoBackup Amazon S3 backups for MySQL | XaprbAfter I wrote about things you need to know about MySQL backups , a customer contacted me and asked me what I know about SecoBackup for ...
     2  +3 2014 sep 02mysql full joinHow to simulate FULL OUTER JOIN in MySQL | XaprbIn this article I'll show several ways to emulate a FULL OUTER join on a RDBMS that doesn't support it, as is the case with even the most recent ...
     2  +1 2014 aug 31mysql full outer joinIn this article I'll show several ways to emulate a FULL OUTER join on a RDBMS ... as is the case with even the most recent versions of MySQL .
     2  +8 2014 aug 16primary unique indexThe difference between a unique index and primary key in MySQL There's a really important difference between a unique index (MySQL's answer to a “unique constraint”) and a primary key in MySQL. Please ...
     2  +11 2014 aug 02block table mysqlHow to find out who is locking a table in MySQL | XaprbHow to find out who is locking a table in MySQL ... isn't usually helpful in finding out what transaction is blocking something from happening.
     3  -1 2014 sep 29group by maxHow to select the first/least/ max row per group in SQL | XaprbHere are some common SQL problems, all of which have related solutions: how do I find the most recent log entry for each program? How do I ...
     3  +6 2014 sep 22mysql variablesAdvanced MySQL user variable techniques | XaprbMySQL's user variables have interesting properties that enable the useful techniques I wrote about in recent articles. One property is that you ...
     3  +6 2014 sep 15optimize table in mysqlHow often should you use OPTIMIZE TABLE ? | XaprbMany times I've heard people advise on “best practices” for a MySQL database. This often includes routine maintenance, such as “you should ...
     3  +7 2014 aug 18mysql update or insertHow to write flexible INSERT and UPDATE statements in MySQL MySQL provides several variations on INSERT and UPDATE to allow inserting and updating exactly the desired data. These features provide a ...
     3  +11 2014 aug 18notebook for journalingUltimate notebook and journal face-off | XaprbIf you're like me, you spend so much time typing on a computer that a good notebook or journal is one of life's finer pleasures. I've kept a diary ...
     4  +17 2014 sep 29mysql show variablesMySQL's user variables have interesting properties that enable the useful ... In this post I'll show you how to make sure your variables get ...
     4  -1 2014 sep 18if not existsHow to write INSERT IF NOT EXISTS queries in standard SQL | XaprbIf necessary, INSERT IF NOT EXISTS queries can be written in a single atomic statement, eliminating the need for a transaction, and without ...
     4  +2 2014 sep 03chameleon books notebookI just can't settle into a long-term relationship with my notebook , ... After assessing a number of books , including some extras provided by my ... small; A (small) Chameleon Like notebook ; A teNues CoolNotes notebook . Whew!
     4  +39 2014 aug 27insert if exist updateMySQL provides several variations on INSERT and UPDATE to ... is probably the fastest of all, especially if very few duplicate keys exist in t2 .
     4  -2 2014 jul 28select redundant rows sqlHow to find duplicate rows with SQL | XaprbThis article shows how to find duplicated rows in a database table. This is a ... select day, count(*) from test group by day HAVING count(*) > 1; ...
     4  ~ 2014 jul 22bose vs sennheiserA review of Bose , Sony, and Sennheiser noise-cancelling ... - XaprbI've used active noise-cancelling headphones for over ten years now, and have owned several pairs of Bose , one of Sony, and most recently a ...
     4  +44 2014 jul 18mysql set variableMySQL lets you assign and read a variable at the same time. This is familiar in many programming languages where an assignment can be an ...
     5  +2 2014 sep 291093 you can't specify target tableHow to select from an update target in MySQL | XaprbMySQL doesn't allow referring to a table that's targeted for update in a ... is ERROR 1093 (HY000): You can't specify target table 'apples' for ...
     5  -2 2014 sep 29mysql outer join
     5  +7 2014 sep 11perl dispatchFive great Perl programming techniques to make your life fun again I'm going to use Perl to demonstrate some techniques to accomplish ..... My favorite technique for this is to use a dispatch table of coderefs ...
     5  +6 2014 sep 10auto mount flash in gentooHow to auto - mount removable devices in GNU/Linux | Xaprb... an auto - mount feature to detect and mount devices, such as USB flash drives, ... In this article I'll show you how to get auto - mounting without ... I've browsed around the Gentoo forums, and I see dozens of ways people do it.
     5  +2 2014 sep 10mysql group by maxHow to select the first/least/ max row per group in SQL .... This theoretically ought to work if MySQL orders by the GROUP BY criteria, which it ...
     5  +5 2014 aug 23mysql license costWhen are you required to have a commercial MySQL license ? | XaprbAs you may know, MySQL has a dual- licensing model. You can get the source under the GPL version 2, or you can buy a commercial license .
     5  +42 2014 aug 19mysql num rowHow to number rows in MySQL | XaprbHow to number rows in MySQL . I wrote before about a generic, cross-platform way to simulate the SQL ROW_NUMBER() function in any ...
     5  ~ 2014 aug 13insert id not exists
     5  +3 2014 aug 10mysql primary key indexThere's a really important difference between a unique index ( MySQL's answer to a “unique constraint”) and a primary key in MySQL . Please ...
     5  +5 2014 aug 04mysql enterprise monitoring toolHow much memory does MySQL Enterprise Monitor's agent use After last week's post on agents versus agentless monitoring systems, I got a lot of email. One, from a customer whose name I am not permitted ...
     5  +15 2014 aug 02lock table mysqlMySQL is adding more tools to monitor its internals with every new release, but one thing it still lacks is a way to find out who is locking what, ...
     5  +15 2014 jul 24select and update mysqlMySQL doesn't allow referring to a table that's targeted for update in a FROM clause, which can be frustrating. There's a better way than ...
     5  +55 2014 jul 23update or insert
     5  ~ 2014 jul 18gnucash database formatGnuCash to MySQL export script | XaprbThe default data format is XML, but the GnuCash developers also have support for storing the data in a PostgreSQL database . Unfortunately ...
     5  +2 2014 jul 17mysql insert bitWhy you should not use BIT columns in MySQL | XaprbMySQL implements the BIT data type differently in different versions, and ... mysql > create table test (i bit not null default 0); mysql > insert into ...
     6  +12 2014 sep 29mysql left outer joinA standard SQL FULL OUTER join is like a LEFT or RIGHT join , except that it includes all rows from both tables, matching them where possible ...
     6  +4 2014 sep 27mysql select everyHow to select the first/least/max row per group in SQL | XaprbIn general, these types of “ select the extreme from each group” ... MySQL -specific and generic techniques to assign a number to each row in a ...
     6  +1 2014 sep 21sennheiser noise cancelling headphonesA review of Bose, Sony, and Sennheiser noise-cancelling headphonesI've used active noise - cancelling headphones for over ten years now, and have owned several pairs of Bose, one of Sony, and most recently a ...
     6  +76 2014 aug 24time series databaseTime - Series Databases and InfluxDB | XaprbTime - series databases are of particular interest to me these days. Not only is VividCortex working with large-scale time-series data, but it's a ...
     6  +30 2014 aug 13mysql if not existsIf necessary, INSERT IF NOT EXISTS queries can be written in a single atomic ... to do flexible INSERT and UPDATE statements in MySQL .
     6  +8 2014 aug 12monitor load serverHow to monitor server load on GNU/Linux | XaprbThis article introduces six methods and 12 tools for monitoring system load , performance and related information on GNU/Linux and similar ...
     6  +10 2014 aug 11mysql table lock
     6  +13 2014 aug 11mysql query analyzerAn alternative to the MySQL Query Analyzer | XaprbMySQL just released their new MySQL Query Analyzer (link to a trial), and recently wrote up an interview with Mark Matthews about it.
     6  +14 2014 jul 29monitor server load
     7  -2 2014 oct 01insert or update
     7  -5 2014 sep 30sql insert if not exists
     7  +11 2014 sep 24mysql crc325 ways to make hexadecimal identifiers perform better on MySQL I'll speak mostly about MySQL here, but the same techniques apply almost .... mysql > alter table t add crc int unsigned not null, add key( crc ); ...
     7  -2 2014 sep 23innodb inspect tableHere's the situation: you are trying to update a table and every time ... These are all printed out in the text of SHOW ENGINE INNODB STATUS .
     7  +5 2014 sep 19mysql query execution orderHow MySQL really executes a query | XaprbThere is so much misinformation out there about how MySQL works. ... COUNT( col1) FROM users WHERE userid IN( SELECT userid FROM othertbl ) ORDER BY userid DESC;. The steps to execute this query are as follows:.
     7  -2 2014 sep 08outer join mysql
     7  +5 2014 aug 29mysql profiler queryHow to profile a query in MySQL | XaprbWhen people discuss query optimization on MySQL , or say a query ... This article explains how to really profile a query – what to measure, how ...
     7  +36 2014 aug 18primary key mysql
     7  +4 2014 aug 17sql find duplicateThis article shows how to find duplicated rows in a database table. This is a very common beginner question. The basic technique is ...
     7  +14 2014 aug 11lock tables mysql
     7  +11 2014 aug 09mysql table comparisonAn algorithm to find and resolve data differences between MySQL There's Giuseppe Maxia's work in remote MySQL table comparison . I based the MySQL Table Checksum tool on some of this work. Read the ...
     7  +1 2014 aug 04was ist server loasd
     7  +5 2014 jul 30mysql show profileMySQL provides two main tools for understanding query performance: EXPLAIN and SHOW STATUS . Most MySQL developers know about ...
     7  +38 2014 jul 20mysql replication syncHow to sync tables in master-master MySQL replication | XaprbSuppose you have a master-master replication setup, and you know one of the tables has the wrong data. How do you re- sync it with the other ...
     7  +5 2014 jul 17remove duplicate articles mysqlHow to delete duplicate rows with SQL, Part 2 | XaprbBy reader request, this article explains ways to remove duplicate rows ... uses advanced user-variable techniques on MySQL to delete the rows.
     8  ~ 2014 sep 28mysql primary key
     8  -1 2014 sep 20mysql optimize table
     8  +31 2014 sep 18lock tablesHere's the situation: you are trying to update a table and every time you issue the query, it hangs until it times out and tells you the lock wait ...
     8  +56 2014 sep 09optimize tableThis often includes routine maintenance, such as “you should run OPTIMIZE TABLE on all of your InnoDB tables once a week to defragment ...
     8  -2 2014 sep 08mk table sync command lineGet Maatkit fast from the command line | XaprbNow, at the command line , you can just run this: wget d the scenes are ...
     8  +59 2014 aug 17full outer join
     8  +15 2014 aug 12server load monitor
     8  +23 2014 jul 30mysql no of rows
     8  -1 2014 jul 25unique key mysqlThere's a really important difference between a unique index ( MySQL's answer to a “ unique constraint”) and a primary key in MySQL . Please ...
     8  +1 2014 jul 22mysql interprise serverWhat would make me buy MySQL Enterprise ? | XaprbIf the MySQL Enterprise Server were a good thing, I'd recommend it to my consulting clients. I'd suggest we start using it at my employer, too.
     9  -1 2014 sep 29mysql variable
     9  +2 2014 sep 24mysql deadlockHow to deliberately cause a deadlock in MySQL | XaprbI know only two solutions to this problem: 1) restart MySQL and 2) cause a small deadlock so the LAST DETECTED DEADLOCK section shrinks ...
     9  +92 2014 sep 16specified key was too longHow to understand key length limitations in MySQL | Xaprbcreate table test(c varchar(250), d varchar(250), primary key(c,d)); ERROR 1071 ( 42000): Specified key was too long ; max key length is 1000 ...
     9  +92 2014 sep 09max sql
     9  +14 2014 aug 25check server load
     9  +9 2014 aug 12linux server loadHow to monitor server load on GNU/ Linux | XaprbThis article introduces six methods and 12 tools for monitoring system load , performance and related information on GNU/ Linux and similar ...
     9  +1 2014 jul 24mysql right join
     9  +1 2014 jul 21mysql enterprise server
     10  +27 2014 sep 26insert select mysqlMySQL provides several variations on INSERT and UPDATE to allow ... delete t2 from t2 inner join t1 on a = d; insert into t1 select * from t2;.
     10  ~ 2014 aug 30group by in mysqlIn general, these types of “select the extreme from each group ” queries .... This theoretically ought to work if MySQL orders by the GROUP BY ...
     10  +15 2014 aug 27high performance mysqlProgress on High Performance MySQL , 4th Edition | XaprbWith the 3rd edition of High Performance MySQL finally complete, I've begun work on the 4th edition. As you know, technology moves much ...
     10  +7 2014 aug 14mysql innodb free tablespaceMeasuring free space in InnoDB's global tablespace | XaprbIn older versions of MySQL , the SHOW TABLE STATUS command showed the amount of space free in the tablespace as an entry in the ...
     10  +48 2014 aug 14mysql update joinHow to use ORDER BY and LIMIT on multi-table updates in MySQL How to use ORDER BY and LIMIT on multi-table updates in MySQL ... Normally you can't self- join the update target in a multi-table UPDATE  ...
     10  +53 2014 aug 14mysql sub queryHow to optimize subqueries and joins in MySQL | XaprbSince MySQL doesn't provide really good tools to profile queries, I ran ... is a join, but the second query is a dependent (correlated) subquery , ...
     10  +3 2014 aug 02em dash mysqlHow to find and fix invalid character data in MySQL | XaprbMySQL usually ignores trailing spaces when comparing character data ... curly quotes (characters 145-148) and the em - dash (character 151).
     10  +4 2014 jul 28mysql status monitorHow to monitor MySQL status and variables with innotop | XaprbThis is one in a series of articles on how to use innotop, a MySQL and InnoDB monitor . In this article I'll explain how innotop can make it much ...
     10  +22 2014 jul 27insert into joinSuppose I wish to insert the data from t2 into t1 . This data would ... delete t2 from t2 inner join t1 on a = d; insert into t1 select * from t2;. The first ...
     10  ~ 2014 jul 22sql optimizer for mysqlI'll also show you some tricks you can use to get MySQL to optimize queries
     10  +4 2014 jul 17mysql num resultsThere is a much more efficient way to do this on MySQL with user ... set @ num = 1; select type, variety, @ num := if(@type = type, @ num + 1, ...
     11  +7 2014 sep 10mysql loopMySQL isn't limited to nested- loop joins | XaprbMySQL isn't limited to nested- loop joins. I have followed the “Use the Index, Luke! ” blog for a while. Today Marcus wrote that (I'll paraphrase) ...
     11  +7 2014 aug 25server load linux
     11  +90 2014 aug 24update table in mysqlHow to use ORDER BY and LIMIT on multi- table updates in MySQL One of my colleagues recently redesigned a system for scheduling work, and needed to write a multiple- table UPDATE with ORDER BY and ...
     11  +24 2014 aug 14mysql order by multipleOne of my colleagues recently redesigned a system for scheduling work, and needed to write a multiple -table UPDATE with ORDER BY and ...
     11  +90 2014 aug 13limit in mysqlOne of my colleagues recently redesigned a system for scheduling work, and needed to write a multiple-table UPDATE with ORDER BY and ...
     11  +90 2014 aug 12sql query analyzerMySQL just released their new MySQL Query Analyzer (link to a trial), ... If you've ever administered Microsoft SQL Server, you know what kind ...
     11  +12 2014 aug 12mysql lock tables
     11  +3 2014 aug 08mysql table syncSuppose you have a master-master replication setup, and you know one of the tables has the wrong data. How do you re- sync it with the other ...
     11  +20 2014 aug 08beginning database designA Review of Beginning Database Design by Clare Churcher | XaprbBeginning Database Design : From Novice to Professional. By Clare Churcher, Apress, 2007. Page count: 230 pages. (Here's a link to the ...
     11  ~ 2014 jul 31my sql errorMySQL's ERROR 1025 explained | XaprbMySQL issues a cryptic error message, “ Error on rename,” when you try to alter a table in such a way that it would break a foreign key constraint ...
     11  +21 2014 jul 26migrating oracle to mysql50 things to know before migrating Oracle to MySQL | XaprbA while back I was at a seminar on migrating database applications to MySQL . A lot of the attendees were Oracle users. Based on their ...
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