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How to request a random row in SQL?
...andom row from a database table. It goes through methods for doing this in MySQL, PostgreSQL, Microsoft SQL Server, IBM DB2 and Oracle (the following is copied from that link):
Select a random row with MySQL:
SELECT column FROM table
ORDER BY RAND()
LIMIT 1
Select a random row with PostgreSQL:
...
Breadth First Vs Depth First
...
Both kinds of traversal can be achieved with the pseudocode:
Store the root node in Container
While (there are nodes in Container)
N = Get the "next" node from Container
Store all the children of N in Container
Do some work on N
The difference between the two traversal orders lies in ...
How does the vim “write with sudo” trick work?
...ve probably seen the command that allows you to write on a file that needs root permission, even when you forgot to open vim with sudo:
...
Check whether a path is valid in Python without creating a file at the path's target
...dity," we mean the syntactic correctness of a pathname with respect to the root filesystem of the current system – regardless of whether that path or parent directories thereof physically exist. A pathname is syntactically correct under this definition if it complies with all syntactic requirement...
Access nested dictionary items via a list of keys?
...uce # forward compatibility for Python 3
import operator
def get_by_path(root, items):
"""Access a nested object in root by item sequence."""
return reduce(operator.getitem, items, root)
def set_by_path(root, items, value):
"""Set a value in a nested object in root by item sequence.""...
How to configure Ruby on Rails with no database?
...o current need for a database. I know I could create an empty database in MySQL and go from there, but does anyone know a better way to run Rails without a database?
...
How do I detect if software keyboard is visible on Android Device or not?
...oolean opened) {
print("keyboard " + opened);
}
// ContentView is the root view of the layout of this activity/fragment
contentView.getViewTreeObserver().addOnGlobalLayoutListener(
new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
...
Errors: “INSERT EXEC statement cannot be nested.” and “Cannot use the ROLLBACK statement within an I
...ble approach: -
CREATE PROCEDURE SP3 as
BEGIN
SELECT 1, 'Data1'
UNION ALL
SELECT 2, 'Data2'
END
go
CREATE PROCEDURE SP2 as
BEGIN
if exists (select * from tempdb.dbo.sysobjects o where o.xtype in ('U') and o.id = object_id(N'tempdb..#tmp1'))
INSERT INTO #tmp1
...
How to show first commit by 'git log'?
... answer was posted.)
Explanation
Technically, there may be more than one root commit. This happens when multiple previously independent histories are merged together. It is common when a project is integrated via a subtree merge.
The git.git repository has six root commits in its history graph (o...
How can I configure Logback to log different levels for a logger to different destinations?
...n</pattern>
</encoder>
</appender>
<root level="INFO">
<appender-ref ref="STDOUT"/>
<appender-ref ref="STDERR" />
</root>
</configuration>
...