大约有 46,000 项符合查询结果（耗时：0.0687秒） [XML]
Using LIMIT within GROUP BY to get N results per group?
...to get all years into a single column, grouped by id and ordered by rate:
SELECT id, GROUP_CONCAT(year ORDER BY rate DESC) grouped_year
FROM yourtable
GROUP BY id
Result:
-----------------------------------------------------------
| ID | GROUPED_YEAR |...
jQuery UI Tabs - How to Get Currently Selected Tab Index
...answer is there - use ui.index property to get the current index in the tabselect event.....
– redsquare
Nov 5 '09 at 12:27
17
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Default text which won't be shown in drop-down list
I have a select which initially shows Select language until the user selects a language. When the user opens the select, I don't want it to show a Select language option, because it's not an actual option.
...
Is there any difference between GROUP BY and DISTINCT
...CT and distinct by UNION cause an oracle error, but GROUP BY worked; I was selecting only 1 column from a view and not using any aggregation; I'm still baffled why it required it, but it does confirm there is some difference in the execution. As others point out, it also lets you GROUP BY columns no...
Why does AngularJS include an empty option in select?
...efined in the specification at http://docs.angularjs.org/api/ng.directive:select , I still get an empty option as the first child of select element.
...
How do I do top 1 in Oracle?
...
If you want just a first selected row, you can:
select fname from MyTbl where rownum = 1
You can also use analytic functions to order and take the top x:
select max(fname) over (rank() order by some_factor) from MyTbl
...
How can I select rows with most recent timestamp for each key value?
...r data. Each row has a sensor id, a timestamp, and other fields. I want to select a single row with latest timestamp for each sensor, including some of the other fields.
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Difference between DateTime and Time in Ruby
...12 00:00:00 +0000
So it's reassuring that DateTime can handle blog posts from Aristotle.
When choosing one, the differences are somewhat subjective now. Historically DateTime has provided better options for manipulating it in a calendar fashion, but many of these methods have been ported over to ...
How to Join to first row
...
SELECT Orders.OrderNumber, LineItems.Quantity, LineItems.Description
FROM Orders
JOIN LineItems
ON LineItems.LineItemGUID =
(
SELECT TOP 1 LineItemGUID
FROM LineItems
W...
How to delete duplicates on a MySQL table?
...n an index is going to be slow for large tables. Wouldn't it be better to SELECT MAX(ID) FROM t GROUP BY unique and then JOIN to an exact match of ID to MAX(ID)?
– ebyrob
Nov 10 '16 at 16:31
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