大约有 40,000 项符合查询结果（耗时：0.0212秒） [XML]
What is the most efficient/elegant way to parse a flat table into a tree?
...port recursive queries in standard syntax.
WITH RECURSIVE MyTree AS (
SELECT * FROM MyTable WHERE ParentId IS NULL
UNION ALL
SELECT m.* FROM MyTABLE AS m JOIN MyTree AS t ON m.ParentId = t.Id
)
SELECT * FROM MyTree;
I tested recursive queries in MySQL 8.0 in my presentation Recursive ...
How to check Oracle database for long running queries
...
This one shows SQL that is currently "ACTIVE":-
select S.USERNAME, s.sid, s.osuser, t.sql_id, sql_text
from v$sqltext_with_newlines t,V$SESSION s
where t.address =s.sql_address
and t.hash_value = s.sql_hash_value
and s.status = 'ACTIVE'
and s.username <> 'SYSTEM'
ord...
ORACLE 常用日期函数 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...的日期。如果给出一负数，返回值日期之前几个月日期。select add_months(to_date(&...ADD_MONTHS函数在输入日期上加上指定的几个月返回一个新的日期。如果给出一负数，返回值日期之前几个月日期。
select add_months(to_date('20150201','yyyymmd...
Database Design for Tagging
... to rebuilt every time a question has a tag added or removed. A query like select * from question q inner join question_has_tag qt where tag_id in (select tag_id from tags where (what we want) minus select tag_id from tags where (what we don't) should be fine and scale out assuming the right b-tree ...
MySQL - UPDATE query based on SELECT Query
...can go here
ANSI SQL syntax:
UPDATE tableA SET validation_check =
(SELECT if(start_DTS > end_DTS, 'VALID', '') AS validation_check
FROM tableA
INNER JOIN tableB ON name_A = name_B
WHERE id_A = tableA.id_A)
Pick whichever one seems most natural to you.
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How can I copy the output of a command directly into my clipboard?
...mewhere else other than a X application, try this one:
cat file | xclip -selection clipboard
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How to add ASP.NET 4.0 as Application Pool on IIS 7, Windows 7
...t to Windows 7.
One of the things that I need to run the application is to select ASP.NET v4.0 as the application pool within IIS.
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Counting the number of option tags in a select tag in jQuery
How do I count the number of <option> s in a <select> DOM element using jQuery?
8 Answers
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-didSelectRowAtIndexPath: not being called
...de a tab view. In my UITableViewController , I implemented -tableView:didSelectRowAtIndexPath: , but when I select a row at runtime, the method isn't being called. The table view is being populated though, so I know that other tableView methods in my controller are being called.
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Linq: What is the difference between Select and Where
The Select and Where methods are available in Linq. What should every developer know about these two methods? For example: when to use one over the other, any advantages of using one over the other, etc.
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