大约有 47,000 项符合查询结果（耗时：0.0679秒） [XML]
MySQL select 10 random rows from 600K rows fast
How can I best write a query that selects 10 rows randomly from a total of 600k?
26 Answers
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Export database schema into SQL file
...ht click the database you want to generate scripts for (not the table) and select tasks - generate scripts
Next, select the requested table/tables, views, stored procedures, etc (from select specific database objects)
Click advanced - select the types of data to script
Click Next and finish
MSDN...
How to get multiple counts with one SQL query?
...tion. This is basically the same thing as a PIVOT function in some RDBMS:
SELECT distributor_id,
count(*) AS total,
sum(case when level = 'exec' then 1 else 0 end) AS ExecCount,
sum(case when level = 'personal' then 1 else 0 end) AS PersonalCount
FROM yourtable
GROUP BY distributor_id
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MySQL: Insert record if not exists in table
...oDB;
Insert a record:
INSERT INTO table_listnames (name, address, tele)
SELECT * FROM (SELECT 'Rupert', 'Somewhere', '022') AS tmp
WHERE NOT EXISTS (
SELECT name FROM table_listnames WHERE name = 'Rupert'
) LIMIT 1;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0
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INSERT with SELECT
I have a query that inserts using a select:
8 Answers
8
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HTML form readonly SELECT tag/input
According to HTML specs, the select tag in HTML doesn't have a readonly attribute, only a disabled attribute. So if you want to keep the user from changing the dropdown, you have to use disabled .
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How to select option in drop down using Capybara
I'm trying to select an item from a drop down menu using Capybara (2.1.0).
9 Answers
9...
jQuery - getting custom attribute from selected option
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You're adding the event handler to the <select> element.
Therefore, $(this) will be the dropdown itself, not the selected <option>.
You need to find the selected <option>, like this:
var option = $('option:selected', this).attr('mytag');
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安装Adobe cs6出错：“please uninstall and reinstall the product” - 环...
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配置错误
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请卸载并重新安装该产品。
如果此问题仍然存在，请与 Adobe 技术支持联系以获得帮助，并提供屏幕下方显示的错误代码。
错误:16
http://www.adobe.com/cn/support/
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Unicode and UTF-8 - 综合 - 清泛IT论坛，有思想、有深度
Unicode预订的编码空间大小为0x0-0x10FFFF，最多可以容纳1114112（100多万）个字符，实际上并不能使用这么多的空间，于是编码方式出现了两种：ucs-2(BMP)和ucs-4 编码方式，其中,bmp是Basic Multilingual Plane的简写。
一个字符的Unicode编码(...