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Postgresql aggregate array
...
What I understand you can do something like this:
SELECT p.p_name,
STRING_AGG(Grade.Mark, ',' ORDER BY Grade.Mark) As marks
FROM Student
LEFT JOIN Grade ON Grade.Student_id = Student.Id
GROUP BY Student.Name;
EDIT
I am not sure. But maybe something like this then:
SELECT p.p_name,
...
Rails where condition using NOT NIL
...S NOT NULL
Note that this syntax reports a deprecation (it talks about a string SQL snippet, but I guess the hash condition is changed to string in the parser?), so be sure to add the references to the end:
Foo.includes(:bar).where.not(bars: {id: nil}).references(:bar)
DEPRECATION WARNING: I...
Setting log level of message at runtime in slf4j
...mentation.
*/
public static void log(Logger logger, Level level, String txt) {
if (logger != null && level != null) {
switch (level) {
case TRACE:
logger.trace(txt);
break;
case DEBUG:
logge...
Save Screen (program) output to a file
...cess:
logfile test.log
logfile flush 1
log on
logtstamp after 1
logtstamp string "[ %t: %Y-%m-%d %c:%s ]\012"
logtstamp on
If you want to do it "on the fly", you can change logfile automatically.
\012 means "new line", as using \n will print it on the log file: source.
Start your command with the...
How to get JSON response from http.Get
...r myClient = &http.Client{Timeout: 10 * time.Second}
func getJson(url string, target interface{}) error {
r, err := myClient.Get(url)
if err != nil {
return err
}
defer r.Body.Close()
return json.NewDecoder(r.Body).Decode(target)
}
Example use:
type Foo struct {
...
AsyncTask threads never die
...t will have from 5 to 128 threads. If there are more than 5 threads, those extra threads will stick around for at most 10 seconds before being removed. (note: these figures are for the presently-visible open source code and vary by Android release).
Leave the AsyncTask threads alone, please.
...
How do I correctly clone a JavaScript object?
...*/
setTimeout(function(){
var d2 = clone(d1);
alert("d1 = " + d1.toString() + "\nd2 = " + d2.toString());
}, 5000);
The date string for d1 will be 5 seconds behind that of d2. A way to make one Date the same as another is by calling the setTime method, but that is specific to the Date clas...
How to adjust layout when soft keyboard appears
...
+1 That simple? Any extra conditions? What was the image you posted about?
– Roy Lee
May 7 '13 at 4:17
...
What are the differences between a multidimensional array and an array of arrays in C#?
...using System;
using System.Diagnostics;
static class ArrayPref
{
const string Format = "{0,7:0.000} ";
static void Main()
{
Jagged();
Multi();
Single();
}
static void Jagged()
{
const int dim = 100;
for(var passes = 0; passes < 10; ...
How do you crash a JVM?
...Hotspot VM quiet nicely:
public class Crash {
public static void main(String[] args) {
Object[] o = null;
while (true) {
o = new Object[] {o};
}
}
}
This leads to a stack overflow in the GC so you will get no StackOverflowError but a real crash includi...