大约有 13,700 项符合查询结果（耗时：0.0326秒） [XML]
Postgresql GROUP_CONCAT equivalent?
...
This is probably a good starting point (version 8.4+ only):
SELECT id_field, array_agg(value_field1), array_agg(value_field2)
FROM data_table
GROUP BY id_field
array_agg returns an array, but you can CAST that to text and edit as needed (see clarifications, below).
Prior to version 8.4, you...
What is a Question Mark “?” and Colon “:” Operator Used for? [duplicate]
...l of optimization, and if you do, you probably want to use attributes like __builtin_expect anyway.
– Brendan Long
Dec 4 '18 at 17:40
add a comment
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Limit results in jQuery UI Autocomplete
...thank you so much for this! :D so happy I happend to find this solution ^__^
– Alisso
Jan 12 '13 at 5:00
what if one...
Set environment variables on Mac OS X Lion
When someone says "edit your .plist file" or "your .profile" or ".bash_profile" etc, this just confuses me. I have no idea where these files are, how to create them if I have to do that, etc, and also why there seem to be so many different ones (why? Do they do different things?)
...
Creating a jQuery object from a big HTML-string
...TML, which will parse the HTML string to an array of DOM nodes. eg:
var dom_nodes = $($.parseHTML('<div><input type="text" value="val" /></div>'));
alert( dom_nodes.find('input').val() );
DEMO
var string = '<div><input type="text" value="val" /></div>';
$('<...
Configure Microsoft.AspNet.Identity to allow email address as username
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The C# version of this (in App_Code\IdentityModels.cs) is
public UserManager()
: base(new UserStore<ApplicationUser>(new ApplicationDbContext()))
{
UserValidator = new UserValidator<ApplicationUser>(this) { AllowOnlyAlphan...
Importing CommonCrypto in a Swift framework
...e this directory and trigger the rest of the script to run
if [ -d "${BUILT_PRODUCTS_DIR}/CommonCryptoModuleMap" ]; then
echo "${BUILT_PRODUCTS_DIR}/CommonCryptoModuleMap directory already exists, so skipping the rest of the script."
exit 0
fi
mkdir -p "${BUILT_PRODUCTS_DIR}/CommonCryptoMod...
How to only get file name with Linux 'find'?
... of xargs without -n1.
It gives the correct result and it's the fastest ¯\_(ツ)_/¯
(basename takes only 1 path argument but xargs will send them all (actually 5000) without -n1. does not work on linux and openbsd, only macOS...)
Some bigger numbers from a linux system to see how -execdir helps...
Is the != check thread safe?
...g/Object;
ALOAD 0
GETFIELD test/Test1.a : Ljava/lang/Object;
IF_ACMPEQ L1
...
as we can see it loads field a to local vars twice, it's a non-atomic operation, if a was changed in between by another thread comparison may produce false.
Also, memory visibility problem is relevant here...
How to use mongoimport to import csv
...ecting to: test
> use mydb
switched to db mydb
> db.things.find()
{ "_id" : ObjectId("4d32a36ed63d057130c08fca"), "Name" : "Jane Doe", "Address" : "123 Main St", "City" : "Whereverville", "State" : "CA", "ZIP" : 90210 }
{ "_id" : ObjectId("4d32a36ed63d057130c08fcb"), "Name" : "John Doe", "Addr...