大约有 40,000 项符合查询结果（耗时：0.0720秒） [XML]
'^M' character at end of lines
...ed to the command-line. I don't know on which OS the SQL script was originally created.
16 Answers
...
What is the difference between concurrency, parallelism and asynchronous methods?
Concurrency is having two tasks run in parallel on separate threads. However, asynchronous methods run in parallel but on the same 1 thread. How is this achieved? Also, what about parallelism?
...
When to use Hadoop, HBase, Hive and Pig?
... too huge.
Coming back to the first part of your question, Hadoop is basically 2 things: a Distributed FileSystem (HDFS) + a Computation or Processing framework (MapReduce). Like all other FS, HDFS also provides us storage, but in a fault tolerant manner with high throughput and lower risk of data ...
'IF' in 'SELECT' statement - choose output value based on column values
...tp://dev.mysql.com/doc/refman/5.0/en/control-flow-functions.html.
Additionally, you could handle when the condition is null. In the case of a null amount:
SELECT id,
IF(type = 'P', IFNULL(amount,0), IFNULL(amount,0) * -1) as amount
FROM report
The part IFNULL(amount,0) means when amount ...
MySQL - Make an existing Field Unique
...e you don't have duplicates first, no?
– William T. Mallard
Apr 16 '14 at 20:04
1
Be sure to make...
How to go back in Eclipse?
Is there a way to go back in Eclipse? Basically, when I'm jumping around a big project following the execution flow (ctrl + click and etc.), is there a way to retrace a step? If my code calls a method and I go to the method definition, is there a key combination that will take me back to the calling...
CSS center display inline block?
...me as I need a child element with display: inline-block to be both horizontally and vertically centered within a 100% width parent.
I used Flexbox's justify-content and align-items properties, which respectively allow you to center elements horizontally and vertically. By setting both to center on...
Under what conditions is a JSESSIONID created?
...s created/sent when session is created. Session is created when your code calls request.getSession() or request.getSession(true) for the first time. If you just want to get the session, but not create it if it doesn't exist, use request.getSession(false) -- this will return you a session or null. In...
REST HTTP status codes for failed validation or invalid duplicate
...of issue. The only other alternative is 422 Unprocessable Entity. It actually comes from WebDav but it is perfectly valid to reuse any status code that has been registered with IANA.
– Darrel Miller
Jul 20 '10 at 19:38
...
MySQL: Can't create table (errno: 150)
... child table InnoDB engine. Current create.sql script was using InnoDB for all tables, but I had very very old installation where first script used MyISAM.
– Whome
Apr 8 '13 at 9:50
...