大约有 47,000 项符合查询结果（耗时：0.0806秒） [XML]
Postgresql GROUP_CONCAT equivalent?
...ly):
SELECT id_field, array_agg(value_field1), array_agg(value_field2)
FROM data_table
GROUP BY id_field
array_agg returns an array, but you can CAST that to text and edit as needed (see clarifications, below).
Prior to version 8.4, you have to define it yourself prior to use:
CREATE AGGREGATE ...
Where should I put the log4j.properties file?
...
I know it's a bit late to answer this question, and maybe you already found the solution, but I'm posting the solution I found (after I googled a lot) so it may help a little:
Put log4j.properties under WEB-INF\classes of the project as m>me m>ntioned previously in this thread.
P...
How to do som>me m>thing to each file in a directory with a batch script
How do you iterate over each file in a directory with a .bat or .cmd file?
6 Answers
6...
Understanding recursion [closed]
...ter science, a tree is a structure made up of nodes, where each node has som>me m> number of children that are also nodes, or null. A binary tree is a tree made of nodes that have exactly two children, typically called "left" and "right"; again the children can be nodes, or null. A root is a node that is...
Text size and different android screen sizes
I know, it was discussed already 1000 tim>me m>s, but I can't adjust the text size for different screen sizes. I try to use 'sp' as size units in my custom style:
...
What's the difference between identifying and non-identifying relationships?
...relationship is when the primary key attributes of the parent must not becom>me m> primary key attributes of the child. A good example of this is a lookup table, such as a foreign key on Person.state referencing the primary key of States.state. Person is a child table with respect to States. But a row...
How do you run a Python script as a service in Windows?
...
Yes you can. I do it using the pythoncom libraries that com>me m> included with ActivePython or can be installed with pywin32 (Python for Windows extensions).
This is a basic skeleton for a simple service:
import win32serviceutil
import win32service
import win32event
import servicemana...
In Matplotlib, what does the argum>me m>nt m>me m>an in fig.add_subplot(111)?
Som>me m>tim>me m>s I com>me m> across code such as this:
7 Answers
7
...
HAProxy redirecting http to https (ssl)
I'm using HAProxy for load balancing and only want my site to support https. Thus, I'd like to redirect all requests on port 80 to port 443.
...
Is the “struct hack” technically undefined behavior?
What I am asking about is the well known "last m>me m>mber of a struct has variable length" trick. It goes som>me m>thing like this:
...