大约有 40,000 项符合查询结果（耗时：0.0787秒） [XML]
Postgresql aggregate array
...
Use array_agg: http://www.sqlfiddle.com/#!1/5099e/1
SELECT s.name, array_agg(g.Mark) as marks
FROM student s
LEFT JOIN Grade g ON g.Student_id = s.Id
GROUP BY s.Id
By the way, if you are using Postgres 9.1, you don't need ...
MQTT与TCP的区别 - 创客硬件开发 - 清泛IT社区，为创新赋能！
...ACL访问控制、集群、共享订阅、重要指标dashboard、sysadmin api、插件扩展、对topic或session或clientid的tracing调试等高级功能，大大简化服务器端的开发工作量。实际应用中，只需要写发布和订阅接口函数即可，中间过程对应用开发人...
两种js滑动门(tab切换)效果 - 源码下载 - 清泛网 - 专注C/C++及内核技术
...
thisObj.className = "active";
document.getElementById(tabObj+"_Content"+i).style.display = "block";
}else{
tabList[i].className = "normal";
document.getElementById(tabObj+"_Content"+i).style.display = "none";
}
}
}
</script>
</head>
<body>
<div align...
How to declare a variable in a PostgreSQL query
...WITH () query which can work as a variable, or even tuple of variables. It allows you to return a table of temporary values.
WITH master_user AS (
SELECT
login,
registration_date
FROM users
WHERE ...
)
SELECT *
FROM users
WHERE master_login = (SELECT login
...
difference between fork and branch on github
If I fork a project that's hosted on github. Do I fork all the branches? How do I know which branch my fork is based on? In other words which branch will be downloaded to my PC?
...
How to convert a string to number in TypeScript?
..., or simply use the unary + operator:
var x = "32";
var y: number = +x;
All of the mentioned techniques will have correct typing and will correctly parse simple decimal integer strings like "123", but will behave differently for various other, possibly expected, cases (like "123.45") and corner c...
App store link for “rate/review this app”
... Note - the "type=Purple+Software" has to be there and it has to be literally "Purple Software" - it's not the name of your company, it's a codename for iPhone applications :) I wasted an hour before I figured this out...
– Kuba Suder
Oct 24 '11 at 11:27
...
Why is a div with “display: table-cell;” not affected by margin?
...
Cause
From the MDN documentation:
[The margin property] applies to all elements except elements with
table display types other than table-caption, table and inline-table
In other words, the margin property is not applicable to display:table-cell elements.
Solution
Consider using the bo...
How to remove/delete a large file from commit history in Git repository?
I accidentally dropped a DVD-rip into a website project, then carelessly git commit -a -m ... , and, zap, the repo was bloated by 2.2 gigs. Next time I made some edits, deleted the video file, and committed everything, but the compressed file is still there in the repository, in history.
...
Developing GUIs in Python: Tkinter vs PyQt [closed]
...es a very professional look, not comparable with a toolkit like Swing. The API is extensive and goes beyond the pure GUI things like widgets. It has support for database connectivity, printing, threading (I used it and it works like a charm),... I even use it to generate PDF's (no other external lib...