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PostgreSQL Autoincrement
...
Yes, SERIAL is the equivalent function.
CREATE TABLE foo (
id SERIAL,
bar varchar);
INSERT INTO foo (bar) values ('blah');
INSERT INTO foo (bar) values ('blah');
SELECT * FROM foo;
1,blah
2,blah
SERIAL is just a create table time macro around sequences. You can not alter SERIAL...
What's the $unwind operator in MongoDB?
...f adding and obtaining the data from your storage locations.
That being said, in order to understand the concept behind the $unwind parameter, you first must understand what the use case that you are trying to quote is saying. The example document from mongodb.org is as follows:
{
title : "this i...
How to select rows with no matching entry in another table?
...
Here's a simple query:
SELECT t1.ID
FROM Table1 t1
LEFT JOIN Table2 t2 ON t1.ID = t2.ID
WHERE t2.ID IS NULL
The key points are:
LEFT JOIN is used; this will return ALL rows from Table1, regardless of whether or not there is a matching row in Table2.
...
How to use NSJSONSerialization
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Your root json object is not a dictionary but an array:
[{"id": "1", "name":"Aaa"}, {"id": "2", "name":"Bbb"}]
This might give you a clear picture of how to handle it:
NSError *e = nil;
NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData: data options: NSJSONReadingMutabl...
UPDATE multiple tables in MySQL using LEFT JOIN
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UPDATE t1
LEFT JOIN
t2
ON t2.id = t1.id
SET t1.col1 = newvalue
WHERE t2.id IS NULL
Note that for a SELECT it would be more efficient to use NOT IN / NOT EXISTS syntax:
SELECT t1.*
FROM t1
WHERE t1.id NOT IN
(
SELECT id
...
How to sort with lambda in Python
...reverse=False)
so without the key=, the function you pass in will be considered a cmp function which takes 2 arguments.
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What is the easiest way to ignore a JPA field during persistence?
...e String token;
TIP:
You can also use JsonInclude.Include.NON_NULL and hide fields in JSON during deserialization when token == null:
@JsonInclude(JsonInclude.Include.NON_NULL)
@Transient
private String token;
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Android add placeholder text to EditText
...Ah, ok. What you're looking for is setHint(int). Simply pass in a resource id of a string from your xml and you're good to go.
EDIT
And in XML, it's simply android:hint="someText"
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How to do a FULL OUTER JOIN in MySQL?
...on you have:
with two tables t1, t2:
SELECT * FROM t1
LEFT JOIN t2 ON t1.id = t2.id
UNION
SELECT * FROM t1
RIGHT JOIN t2 ON t1.id = t2.id
The query above works for special cases where a FULL OUTER JOIN operation would not produce any duplicate rows. The query above depends on the UNION set ope...
How to do this in Laravel, subquery where in
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Consider this code:
Products::whereIn('id', function($query){
$query->select('paper_type_id')
->from(with(new ProductCategory)->getTable())
->whereIn('category_id', ['223', '15'])
->where('active',...