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Oracle 分组后取每组第一条数据 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...据Oracle 分组后取每组第一条数据的SQL如下，亲测有效：SELECT * FROM (SELECT ROW_NUMBER() OVER(PARTITION BY T field1, T Oracle 分组后取每组第一条数据的SQL如下，亲测有效：
SELECT *
FROM (SELECT ROW_NUMBER() OVER(PARTITION BY T.field1, T.field2 ORDER...
nvarchar和varchar相互转换、联合查询 - ORACLE - 清泛IT论坛，有思想、有深度
...atype is NVARCHAR2.
（A表字段c_xxx:varchar，B表c_xxx:nvarchar）
select translate(c_xxx USING NCHAR_CS) from A
union all
select c_xxx from B
或者
select c_xxx from A
union all
select translate(c_xxx USING CHAR_CS) from B
注意：translate函数括号中没有逗号。
1、...
DropDownList's SelectedIndexChanged event not firing
I have a DropDownList object in my web page. When I click on it and select a different value, nothing happens, even though I have a function wired up to the SelectedIndexChanged event.
...
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...
Calendar Recurring/Repeating Events - Best Storage Method
... grabbing the events for the day it's at, the query would look like this:
SELECT EV.*
FROM `events` EV
RIGHT JOIN `events_meta` EM1 ON EM1.`event_id` = EV.`id`
RIGHT JOIN `events_meta` EM2 ON EM2.`meta_key` = CONCAT( 'repeat_interval_', EM1.`id` )
WHERE EM1.meta_key = 'repeat_start'
AND (
...
What does Redis do when it runs out of memory?
...s reached Redis will try to remove keys
# according to the eviction policy selected (see maxmemory-policy).
#
# If Redis can't remove keys according to the policy, or if the policy is
# set to 'noeviction', Redis will start to reply with errors to commands
# that would use more memory, like SET, LPU...
How do you search an amazon s3 bucket?
...to access many nodes at once ala more traditional datastores that offer a (SELECT * FROM ... WHERE ...) (in a SQL model).
What you will need to do is perform ListBucket to get a listing of objects in the bucket and then iterate over every item performing a custom operation that you implement - whic...
How to pass anonymous types as parameters?
...is an anonymous type right? I'm thinking of a case where someone writes a "Select * from" statement and uses an anonymous (or defined) class to define which columns from the query result map to the same named properties on your anonymous object.
– C. Tewalt
Apr...
How do you truncate all tables in a database using TSQL?
...'
EXEC sp_MSforeachtable 'SET QUOTED_IDENTIFIER ON';
IF NOT EXISTS (
SELECT
*
FROM
SYS.IDENTITY_COLUMNS
JOIN SYS.TABLES ON SYS.IDENTITY_COLUMNS.Object_ID = SYS.TABLES.Object_ID
WHERE
SYS.TABLES.Object_ID = OBJECT_ID('?') AND SYS.IDENTITY_COLUMNS.Last_Val...
Using backticks around field names
...backticks, I would assume it lets you get away with ridiculous stuff like
SELECT `id`, `my name`, `another field` , `field,with,comma`
Which does of course generate badly named tables.
If you're just being concise I don't see a problem with it,
you'll note if you run your query as such
EXPLA...