大约有 6,000 项符合查询结果（耗时：0.0408秒） [XML]
What is the most efficient/elegant way to parse a flat table into a tree?
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Now that MySQL 8.0 supports recursive queries, we can say that all popular SQL databases support recursive queries in standard syntax.
WITH RECURSIVE MyTree AS (
SELECT * FROM MyTable WHERE ParentId IS NULL
UNION ALL
SELECT...
PDO Prepared Inserts multiple rows in single query
I am currently using this type of SQL on MySQL to insert multiple rows of values in one single query:
22 Answers
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varbinary to string on SQL Server
...rent things.
If the varbinary is the binary representation of a string in SQL Server (for example returned by casting to varbinary directly or from the DecryptByPassPhrase or DECOMPRESS functions) you can just CAST it
declare @b varbinary(max)
set @b = 0x5468697320697320612074657374
select cast(@...
LoadRunner中参数化技术详解 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...实的记录了所有从客户端发送到服务器的数据，而在进行性能测试的时候，为了...LoadRunner中参数化技术详解
LoadRunner在录制脚本的时候，只是忠实的记录了所有从客户端发送到服务器的数据，而在进行性能测试的时候，为了更...
SQL Server - When to use Clustered vs non-Clustered Index?
...k a good clustered index.
It's the most replicated data structure in your SQL Server database. The clustering key will be part of each and every non-clustered index on your table, too.
You should use extreme care when picking a clustering key - it should be:
narrow (4 bytes ideal)
unique (it's t...
postgres default timezone
I installed PostgreSQL 9 and the time it is showing is 1 hour behind the server time.
7 Answers
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How to randomly select rows in SQL?
I am using MSSQL Server 2005. In my db, I have a table "customerNames" which has two columns "Id" and "Name" and approx. 1,000 results.
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Nginx url重写rewrite实例详解 - 更多技术 - 清泛网移动版 - 专注C/C++及内核技术
...inx_url_rewrite在nginx中实现url重写，学习rewrite的具体用法，包括301重定向的内容等，希望对大家有所帮助。nginx rewrite 实现二级域名跳转
当访问http://www.jbyuan.com跳转到http://www.jbyuan.com/nvxingjiankang/
方法一：
这种方法浏览器地址会...
How to generate the “create table” sql statement for an existing table in postgreSQL
I have created a table in postgreSQL. I want to look at the SQL statement used to create the table but cannot figure it out.
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How to get cumulative sum
...in @t t2 on t1.id >= t2.id
group by t1.id, t1.SomeNumt
order by t1.id
SQL Fiddle example
Output
| ID | SOMENUMT | SUM |
-----------------------
| 1 | 10 | 10 |
| 2 | 12 | 22 |
| 3 | 3 | 25 |
| 4 | 15 | 40 |
| 5 | 23 | 63 |
Edit: this is a generalized...