大约有 48,000 项符合查询结果（耗时：0.0412秒） [XML]
Is having an 'OR' in an INNER JOIN condition a bad idea?
... a MERGE JOIN.
It can be expressed as a concatenation of two resultsets:
SELECT *
FROM maintable m
JOIN othertable o
ON o.parentId = m.id
UNION
SELECT *
FROM maintable m
JOIN othertable o
ON o.id = m.parentId
, each of them being an equijoin, however, SQL Server's optimiz...
How do I drop a function if it already exists?
...
IF EXISTS (
SELECT * FROM sysobjects WHERE id = object_id(N'function_name')
AND xtype IN (N'FN', N'IF', N'TF')
)
DROP FUNCTION function_name
GO
If you want to avoid the sys* tables, you could instead do (from here in example A...
What is the difference between Views and Materialized Views in Oracle?
... you. The downside of a view is that its performance depends on how good a select statement the view is based on. If the select statement used by the view joins many tables, or uses joins based on non-indexed columns, the view could perform poorly.
Materialized views
They are similar to regular vi...
How to automatically indent source code?
...
Ctrl+E, D - Format whole doc
Ctrl+K, Ctrl+F - Format selection
Also available in the menu via Edit|Advanced.
Thomas
Edit-
Ctrl+K, Ctrl+D - Format whole doc in VS 2010
share
|
...
Two single-column indexes vs one two-column index in MySQL?
... the statement I provided.
Additionally, MySQL can only use one index per SELECT so a covering index would be the best means of optimizing your queries.
share
|
improve this answer
|
...
How do I grant myself admin access to a local SQL Server instance?
...he "SQL Server Configuration Manager", right click the server instance and select properties, go to the tab "Startup Parameters" and add -m.
– maets
May 5 '15 at 13:32
...
Formatting code in Notepad++
...X -> HTML Tidy -> Tidy: Reindent XML
Remember to have the HTML code selected before you do this.
share
|
improve this answer
|
follow
|
...
Explain ExtJS 4 event handling
...js4.1)
Lets say we have a controller Station (Sencha MVC examples) with a select box:
Ext.define('Pandora.controller.Station', {
extend: 'Ext.app.Controller',
...
init: function() {
this.control({
'stationslist': {
selectionchange: this.onStationSel...
How do I temporarily disable triggers in PostgreSQL?
...ct = 'disable';
else
act = 'enable';
end if;
for r in select c.relname from pg_namespace n
join pg_class c on c.relnamespace = n.oid and c.relhastriggers = true
where n.nspname = nsp
loop
execute format('alter table %I %s trigger all', r.relname, act)...
How to fix/convert space indentation in Sublime Text?
...> Indentation
It should read:
Indent using spaces [x]
Tab width: 2
Select:
Convert Indentation to Tabs
Then Select:
Tab width: 4
Convert Indentation to Spaces
Done.
share
|
improve t...