大约有 40,000 项符合查询结果（耗时：0.0266秒） [XML]
Simplest way to do a recursive self-join?
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WITH q AS
(
SELECT *
FROM mytable
WHERE ParentID IS NULL -- this condition defines the ultimate ancestors in your chain, change it as appropriate
UNION ALL
SELECT m.*
FROM mytable m
...
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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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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App Inventor 2 试验组件 · App Inventor 2 中文网
...询问问题，连续的对话将记住先前对话中的信息，使用 重置对话 方法重置开始新的对话。
重置对话()
重置当前对话，聊天机器人在回复时会忘记之前的任何对话。
Firebase数据库
Firebase 组件与 Web 服务通信以存储并获取...
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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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...
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...