大约有 44,000 项符合查询结果（耗时：0.0500秒） [XML]
Is there a way to access the “previous row” value in a SELECT statement?
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SQL has no built in notion of order, so you need to order by some column for this to be meaningful. Something like this:
select t1.value - t2.value from table t1, table t2
where t1.primaryKey = t2.primaryKey - 1
If you know how to order things but not how to get the previous value given the cu...
How to check if an int is a null
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Of course, for local variable cannot be uninitialized, it's invalid code, Java won't permit it, as declared in its specification.
– Alex
Mar 7 at 21:43
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Is it possible to update a localized storyboard's strings?
...of my application with creating a base.lproj storyboard and 3 string files for it. It was a month ago and after that I added new view controller to app, but this controller's buttons and labels not appear in string files
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How to send an email from JavaScript
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Send an email using only JavaScript
in short:
1. register for Mandrill to get an API key
2. load jQuery
3. use $.ajax to send an email
Like this -
function sendMail() {
$.ajax({
type: 'POST',
url: 'https://mandrillapp.com/api/1.0/messages/send.json',
data: ...
MySQL: Selecting multiple fields into multiple variables in a stored procedure
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Your syntax isn't quite right: you need to list the fields in order before the INTO, and the corresponding target variables after:
SELECT Id, dateCreated
INTO iId, dCreate
FROM products
WHERE pName = iName
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In PHP, how do you change the key of an array element?
I have an associative array in the form key => value where key is a numerical value, however it is not a sequential numerical value. The key is actually an ID number and the value is a count. This is fine for most instances, however I want a function that gets the human-readable name of the arr...
Why use the INCLUDE clause when creating an index?
While studying for the 70-433 exam I noticed you can create a covering index in one of the following two ways.
8 Answers
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Best way to test if a row exists in a MySQL table
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Test with ...EXISTS( SELECT 1/0 FROM someothertable). For SQL Server & Oracle - it makes no difference to use *, 1 or NULL because EXISTS only tests for a boolean based on 1+ of the WHERE criteria matching.
– OMG Ponies
Nov 4 '09 at 23:...
Android: how to make keyboard enter button say “Search” and handle its click?
...) {
if (actionId == EditorInfo.IME_ACTION_SEARCH) {
performSearch();
return true;
}
return false;
}
});
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How do I find which transaction is causing a “Waiting for table metadata lock” state?
I am trying to perform some DDL on a table and SHOW PROCESSLIST results in a " Waiting for table metadata lock " message.
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