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【BLE技术内幕】BLE技术揭秘 - 创客硬件开发 - 清泛IT论坛，有思想、有深度
...个时间点把数据包发送出去，怎么保证数据的完整性，ACK如何接收，如何进行重传，以及如何对链路进行管理和控制等等。LL层只负责把数据发出去或者收回来，对数据进行怎样的解析则交给上面的GAP或者ATTHost Controller Interface，...
Ordering by specific field value first
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There's also the MySQL FIELD function.
If you want complete sorting for all possible values:
SELECT id, name, priority
FROM mytable
ORDER BY FIELD(name, "core", "board", "other")
If you only care that "core" is first and the other values ...
Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
...s another, but it is failing for some reason. With my limited knowledge of MySQL, the only thing that could possibly be suspect is that there is a foreign key on a different table referencing the one I am trying to reference.
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Cast int to varchar
... @JonathanSayce I'm not overly familiar with the ins & outs of MySQL and it might not use something arbitrary, but I wouldn't rely on the MySQL engine to be that smart (no offense to MySQL). In order to be sure you get the proper length, I would always explicitly provide one.
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PDO mysql: How to know if insert was successful
I'm using PDO to insert a record (mysql and php)
7 Answers
7
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MySQL - why not index every field?
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The link is for MS SQL Server; this question is for MySQL
– OMG Ponies
Mar 26 '11 at 23:38
6
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MySQL - SELECT WHERE field IN (subquery) - Extremely slow why?
...B and you only select indexed fields (and things are not too complex) than MySQL will resolve your query using only the indexes, speeding things way up.
General solution for 90% of your IN (select queries
Use this code
SELECT * FROM sometable a WHERE EXISTS (
SELECT 1 FROM sometable b
WHERE...
SQL/mysql - Select distinct/UNIQUE but return all columns?
...ause the behavior on the other columns is unspecified. (The first works in MySQL, if that's what you're using.)
You could fetch the distinct fields and stick to picking a single arbitrary row each time.
On some platforms (e.g. PostgreSQL, Oracle, T-SQL) this can be done directly using window funct...
Simulating group_concat MySQL function in Microsoft SQL Server 2005?
I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).
11 Answers
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Running single test from unittest.TestCase via command line
...import sys
import unittest
test_pattern = 'mytest/module/name.py'
PACKAGE_ROOT_DIRECTORY = os.path.dirname( os.path.realpath( __file__ ) )
loader = unittest.TestLoader()
start_dir = os.path.join( PACKAGE_ROOT_DIRECTORY, 'testing' )
suite = loader.discover( start_dir, test_pattern )
runner = unitt...