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How to shrink/purge ibdata1 file in MySQL
I am using MySQL in localhost as a "query tool" for performing statistics in R, that is, everytime I run a R script, I create a new database (A), create a new table (B), import the data into B, submit a query to get what I need, and then I drop B and drop A.
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SQLAlchemy - Getting a list of tables
...te_engine('postgresql+psycopg2://root:password@localhost/
q = eng.execute('SELECT * FROM pg_catalog.pg_tables')
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Abusing the algebra of algebraic data types - why does this work?
...gard that for the sake of simplicity.
A few initial points:
Note that "union" is probably not the best term for A+B here--that's specifically a disjoint union of the two types, because the two sides are distinguished even if their types are the same. For what it's worth, the more common term is ...
SQL is null and = null [duplicate]
...e t (x int, y int);
insert into t values (null, null), (null, 1), (1, 1);
select 'x = null' as test , x, y from t where x = null
union all
select 'x != null', x, y from t where x != null
union all
select 'not (x = null)', x, y from t where not (x = null)
union all
select 'x = y', x, y from t where ...
When to use Common Table Expression (CTE)
...ing well? Can someone give me a simple example of limitations with regular select, derived or temp table queries to make the case of CTE? Any simple examples would be highly appreciated.
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MySQL: Enable LOAD DATA LOCAL INFILE
I'm running Mysql 5.5 on Ubuntu 12 LTS. How should I enable LOAD DATA LOCAL INFILE in my.cnf?
18 Answers
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How to export a mysql database using Command Prompt?
...ves error "mysqldump: Got error: 1049: Unknown database 'thepassword' when selecting the database" but worked when i delete "-p userpassword"
– Ateş Danış
Jul 7 '13 at 6:35
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What is the difference/usage of homebrew, macports or other package installation tools? [closed]
...to do the same with Homebrew.
MacPorts support groups.
foo@macpro:~/ port select --summary
Name Selected Options
==== ======== =======
db none db46 none
gcc none gcc42 llvm-gcc42 mp-gcc48 none
llvm none mp-llvm-3.3 none
mys...
how to check and set max_allowed_packet mysql variable [duplicate]
...ass', 'dbname' );
// to get the max_allowed_packet
$maxp = $db->query( 'SELECT @@global.max_allowed_packet' )->fetch_array();
echo $maxp[ 0 ];
// to set the max_allowed_packet to 500MB
$db->query( 'SET @@global.max_allowed_packet = ' . 500 * 1024 * 1024 );
So if you've got a query you exp...
Purpose of Unions in C and C++
... @legends2k: any decent optimizer will recognize bitwise operations that select an entire byte and generate code to read/write the byte, same as the union but well-defined (and portable). e.g. uint8_t getRed() const { return colour & 0x000000FF; } void setRed(uint8_t r) { colour = (colour &...