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Overriding a Rails default_scope
...ed_at desc')
end
Foo.reorder('created_at asc')
runs the following SQL:
SELECT * FROM "foos" ORDER BY created_at asc
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Browse the files created on a device by the iOS application I'm developing, on workstation?
...in the bottom half of the window.
In Xcode 6, go to Window -> Devices, select the device, select the app name under Installed Apps, click the settings gearbox, then select Download container.... In finder, double finger tap the package and select Show package contents.
...
LINQ to SQL: Multiple joins ON multiple Columns. Is this possible?
... from child in context.Childs
where child.Parent.col2 == 4
select new
{
childCol1 = child.col1,
parentCol1 = child.Parent.col1,
};
will generate the query
SELECT [t0].[col1] AS [childCol1], [t1].[col1] AS [parentCol1]
FROM [dbo].[Child] AS [...
Insert text with single quotes in PostgreSQL
...token1$escape ' with ''$token1$ is nested$token2$
Pay attention if the $ character should have special meaning in your client software. You may have to escape it in addition. This is not the case with standard PostgreSQL clients like psql or pgAdmin.
That is all very useful for writing plpgsql fu...
Picking a random element from a set
... the buckets that make up the hashset, which allows us to more efficiently select a random elements. If random elements are necessary in Java, it might be worthwhile to define a custom hash set that allows the user to look under the hood. See [boost's docs][1] for a little more in this. [1] boos...
How to select only the first rows for each unique value of a column
...
A very simple answer if you say you don't care which address is used.
SELECT
CName, MIN(AddressLine)
FROM
MyTable
GROUP BY
CName
If you want the first according to, say, an "inserted" column then it's a different query
SELECT
M.CName, M.AddressLine,
FROM
(
SELECT
...
In C#, why is String a reference type that behaves like a value type?
A String is a reference type even though it has most of the characteristics of a value type such as being immutable and having == overloaded to compare the text rather than making sure they reference the same object.
...
Compare two data.frames to find the rows in data.frame 1 that are not present in data.frame 2
...ata.frame(a = 1:3, b=letters[1:3])
require(sqldf)
a1NotIna2 <- sqldf('SELECT * FROM a1 EXCEPT SELECT * FROM a2')
And the rows which are in both data frames:
a1Ina2 <- sqldf('SELECT * FROM a1 INTERSECT SELECT * FROM a2')
The new version of dplyr has a function, anti_join, for exactly the...
JComboBox Selection Change Listener?
...istener() will work, too. You may get 2 ItemEvents, though, one for the deselection of the previously selected item, and another for the selection of the new item. Just don't use both event types!
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如何查看Oracle用户的SQL执行历史记录？ - 数据库(内核) - 清泛网 - 专注C/...
如何查看Oracle用户的SQL执行历史记录？select * from v$sqlarea t order by t LAST_ACTIVE_TIME desc注意 ：执行此语句等等一些相关的语句 必须具有DBA 的权限 虽然
select * from v$sqlarea t order by t.LAST_ACTIVE_TIME desc
注意 ：执行此语句等等一些相...