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10 Newer Entries Showing entries 61 to 70 of 1019 10 Older Entries

Displaying posts with tag: sql (reset)

Free talk on MySQL and Go at Percona MySQL University DC
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If you’re in the Washington, DC area on Sept 12th, be sure to attend Percona University. This is a free 1-day mini-conference to bring developers and system architects up to speed on the latest MySQL products, services and technologies. Some of the topics being covered include Continuent Tungsten; Percona XtraDB Cluster; MySQL Backups in the Real World; MariaDB 10.0; MySQL 5.6 and Percona Server 5.6; Apache Hadoop.

I’ll …

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Stored Routines to easily work with the SQL_MODE
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Versione italiana

Working with the SQL_MODE can be tricky, because it’s a command separated list involving long keywords. To be honest, I hate to rewrite the flags, trying to read an unreadable list, etc. Of course some string functions can help (Justin Swanhart suggests to use REPLACE() to make comma-separated lists readable).

I made a small set of Stored Routines wich allow me to easily show …

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MariaDB/MySQL: Procedures to easily work with the Diagnostics Area
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Versione italiana

UPDATE 2013-08-30: I fixed 2 bugs and create a GitHub repo called sql_diagnostix. Sorry for not doing this before. If I (or someone else) find new bugs, I’ll update the repo.

The problem

To quickly see information about the errors and warnings generated by the last executed statement, we can use SHOW WARNINGS. However this statement’s …

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Announcing MySQL Utilities release-1.3.4 GA
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The MySQL Utilities Team is pleased to announce the latest GA release of
MySQL Utilities. This release marks a milestone of concentrated effort to
expand the use of utilities in more diverse installations through improved
robustness, error handling, and quality.

Many Improvements
There are number such enhancements in this release. In this post we will
highlight a few of the more significant improvements.

  • (new utility) MySQL .frm Reader (mysqlfrm) - read .frm files and generate CREATE statements with or without a server connection.
  • (revised) improved …








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Speaking at Percona University Sept 12th
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I’ll be joining Percona for a free day of MySQL education and insight at their upcoming Percona University Washington DC event on September 12th. My topic is accessing MySQL from Google’s Go programming language. I’ve learned a lot about this over the past year or so, and hopefully I can help you get a quick-start.

If you’re not familiar with Go, it’s the darling of the Hacker News crowd these days. Anything with “Go” in its title gets to …

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Tool of the day: q
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If you work with command line and know your SQL, q is a great tool to use:

q allows you to query your text files or standard input with SQL. You can:

SELECT c1, COUNT(*) FROM /home/shlomi/tmp/my_file.csv GROUP BY c1

And you can:

SELECT all.c2 FROM /tmp/all_engines.txt AS all LEFT JOIN /tmp/innodb_engines.txt AS inno USING (c1, c2) WHERE inno.c3 IS NULL

And you can also combine with your favourite shell commands and tools:

grep "my_term" /tmp/my_file.txt | q "SELECT c4 FROM - JOIN /home/shlomi/static.txt USING (c1)" | xargs touch …
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Working with comma separated list MySQL options
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Over time, some options have crept into the MySQL server which are comma separated lists of options. These include SQL_MODE, optimizer_switch, optimizer_trace and a few other variables.

Optimizer_switch is particularly problematic to work with as it contains many options and is hard to interpret. This is what you usually see when you examine optimizer_switch:




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MariaDB/MySQL Error HANDLERs: advanced uses
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This article explains some advanced uses for MySQL and MariaDB’s error HANDLERs. Some information is in MySQL documentation, but it’s rather sparse. Also, while MySQL manual is probably the best manual ever, I’ve found a major bug in errors documentation. So, these use cases are not so obvious. At least they weren’t for me, so I had to test them.

Notes about the examples in this article

All the examples are tested on MariaDB 10.0.3, but I’m sure that there is not difference in MySQL …

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MySQL “NOT FOUND” errors precedence (docs bug)
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This page in the MySQL documentation says something totally wrong:

http://dev.mysql.com/doc/refman/5.6/en/handler-scope.html

“The precedence of NOT FOUND depends on how the condition is raised:

Normally, a condition in the NOT FOUND class can be handled by an SQLWARNING or NOT FOUND handler, with the SQLWARNING handler taking precedence if both are present. Normal occurrence of NOT FOUND takes place when a cursor used to fetch a set of rows reaches the end of the data set, or for instances of SELECT … INTO var_list …

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SQL Like Comparisons
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SQL tidbits are always valuable and highly searched for by newbies (as opposed to reading the SQL documentation). Sometimes we seasoned SQL developers take for granted little things like when a single- or multiple-character wildcard comparison works. It seems we know what newbies don’t. That you need a wildcard comparison operator not simply and equality comparison operator.

The question posed to me was, “Why doesn’t my wildcard comparison work?” Here’s a simplified example of their question.

SELECT 'Valid' AS "Test"
FROM    dual
WHERE  'Treat' = 'Tre_t'
OR     'Treet' = 'Tre_t';
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10 Newer Entries Showing entries 61 to 70 of 1019 10 Older Entries

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