大约有 20,000 项符合查询结果（耗时：0.1698秒） [XML]
Condition within JOIN or WHERE
...sider these two queries:
SELECT *
FROM dbo.Customers AS CUS
LEFT JOIN dbo.Orders AS ORD
ON CUS.CustomerID = ORD.CustomerID
WHERE ORD.OrderDate >'20090515'
SELECT *
FROM dbo.Customers AS CUS
LEFT JOIN dbo.Orders AS ORD
ON CUS.CustomerID = ORD.CustomerID
AND ORD.OrderDate >'20090515'
The f...
What is JSON and why would I use it?
...cord, struct, dictionary, hash table, keyed list, or associative array.
An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.
JSON Structure
Here is an example of JSON data:
{
"firstName": "John",
"lastName": "Smith",
"add...
How do you add an in-app purchase to an iOS application?
.../ This happens when the IAP needs an external action
// in order to proceeded, like Ask to Buy
RemoveAdsManager.removeAdsDeferred()
break
}
}
}
Now let's add some functions that can be used to start a purchase or a restore purchases:
// ...
How to keep indent for second line in ordered lists via CSS?
...ms, and need consistent vertical spacing, the solution is to add vertical border-spacing to the ol selector, e.g. border-spacing: 0 3px; Normal padding on the table-cell does not work because the number is always only one line.
– RemBem
Nov 12 '15 at 13:42
...
Remove duplicate rows in MySQL
...owing columns:
employee (id, first_name, last_name, start_date, ssn)
In order to delete the rows with a duplicate ssn column, and keeping only the first entry found, the following process can be followed:
-- create a new tmp_eployee table
CREATE TABLE tmp_employee LIKE employee;
-- add a unique...
Do login forms need tokens against CSRF attacks?
...ow I can continue building my website confidently.
– php_learner
Jun 20 '11 at 14:44
21
Login CSR...
What is the difference between the Data Mapper, Table Data Gateway (Gateway), Data Access Object (DA
...
Updated link: github.com/willdurand-edu/php-slides/blob/master/src/common/…
– Fernando Correia
May 10 '16 at 20:51
add a comment
...
How to do this in Laravel, subquery where in
...uery)
{
$query->select(DB::raw(1))
->from('orders')
->whereRaw('orders.user_id = users.id');
})
->get();
This will produce:
select * from users where id in (
select 1 from orders where orders.user_id = users.id
)
...
Why / when would it be appropriate to override ToString?
...r any language that implements it)
SOAP
etc...
Note: Unless you're using PHP because, herp-derp, there's a function for that ::snicker::
Reason 2 - ToString() is not enough:
I have yet to see a language that implements this at the core but I have seen and used variations of this approach in the ...
What is the best way to iterate over a dictionary?
...is completely undeserving of so many upvotes. A dictionary has no implicit order, so using .ElementAt in this context might lead to subtle bugs. Far more serious is Arturo's point above. You'll be iterating the dictionary dictionary.Count + 1 times leading to O(n^2) complexity for an operation that ...