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Reason for Column is invalid in the select list because it is not contained in either an aggregate f
...t of the grouping criteria, nor appear in aggregate functions (SUM, MIN, MAX, etc.).
Fixing it might look like this:
SELECT a, MAX(b) AS x
FROM T
GROUP BY a
Now it's clear that you want the following result:
a x
--------
1 ghi
2 pqr
...
Does MySQL ignore null values on unique constraints?
...multiple NULLs in a column with a unique constraint.
CREATE TABLE table1 (x INT NULL UNIQUE);
INSERT table1 VALUES (1);
INSERT table1 VALUES (1); -- Duplicate entry '1' for key 'x'
INSERT table1 VALUES (NULL);
INSERT table1 VALUES (NULL);
SELECT * FROM table1;
Result:
x
NULL
NULL
1
This is n...
List files with certain extensions with ls and grep
...ust want to get the files from the current dir and only output .mp4 .mp3 .exe files nothing else.
So I thought I could just do this:
...
Download old version of package with NuGet
...
Dependency info and examining what other properties are available: Get-Package -ListAvailable [-Source X] -Filter Common.Logging -AllVersions | select version, dependencies (or '| get-member' to see all the properties)
– Cur...
Does “untyped” also mean “dynamically typed” in the academic CS world?
...s to know that the notion of "type" was invented in the 1930s, in the context of lambda calculus (in fact, even earlier, in the context of set theory). Since then, a whole branch of computational logic has emerged that is known as "type theory". Programming language theory is based on these foundati...
How to perform runtime type checking in Dart?
...
The instanceof-operator is called is in Dart. The spec isn't exactly friendly to a casual reader, so the best description right now seems to be http://www.dartlang.org/articles/optional-types/.
Here's an example:
class Foo { }
main() {
var foo = new Foo();
if (foo is Foo) {
p...
Sort a Custom Class List
...
You can also write the same thing with a lambda expression: list.Sort((a,b) => a.date.CompareTo(b.date));
– Xavier Poinas
Jul 2 '10 at 9:11
2
...
Difference between Apache CXF and Axis
What are the advantages of using Apache CXF over Apache Axis and vice versa?
6 Answers
...
Convert JSON String to Pretty Print JSON output using Jackson
... answered Jan 26 '13 at 0:25
StaxManStaxMan
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How does the Windows Command Interpreter (CMD.EXE) parse scripts?
...
We performed experiments to investigate the grammar of batch scripts. We also investigated differences between batch and command line mode.
Batch Line Parser:
Here is a brief overview of phases in the batch file line parser:
Phase 0) Re...