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Pandas groupby: How to get a union of strings
I have a dataframe like this:
8 Answers
8
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How to truncate a foreign key constrained table?
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As per mysql documentation, TRUNCATE cannot be used on tables with foreign key relationships. There is no complete alternative AFAIK.
Dropping the contraint still does not invoke the ON DELETE and ON UPDATE.
The only solution I can...
How to find the php.ini file used by the command line?
I need to enable pdo_mysql in my EasyPhp environment, so I went to php.ini file and uncommented the following line:
14 Answ...
Can you create nested WITH clauses for Common Table Expressions?
...:
WITH y
AS
(
SELECT x, y, z
FROM MyTable
WHERE [base_condition]
UNION ALL
SELECT x, y, z
FROM MyTable M
INNER JOIN y ON M.[some_other_condition] = y.[some_other_condition]
)
SELECT *
FROM y
You may not need this functionality. I've done the following just to organize my queries ...
Keeping it simple and how to do multiple CTE in a query
...cte2 AS
(
SELECT 2 AS id
)
SELECT *
FROM cte1
UNION ALL
SELECT *
FROM cte2
UNION ALL
SELECT *
FROM cte1
Note, however, that SQL Server may reevaluate the CTE each time it is accessed, so if you are using values like RAND(), NEWID() etc., they may change between...
How do I see all foreign keys to a table or column?
In MySQL, how do I get a list of all foreign key constraints pointing to a particular table? a particular column? This is the same thing as this Oracle question , but for MySQL.
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Windows、Linux开放指定端口 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...口默认是被防火墙拦截禁止外部访问的。本文简要介绍了如何在不关闭防火墙的情况下开放指定端口。Windows篇：
以下步骤中未提供截图的按照默认设置即可：
设置后立即生效。
Linux篇：
vi /etc/sysconfig/iptables
添...
Error in exception handler. - Laravel
...It printed could not find driver. And then I found out I had installed php-mysql, while php7.0-mysql was required. This link also helped me - digitalocean.com/community/tutorials/…
– Udayraj Deshmukh
Jun 18 '17 at 7:21
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What are POD types in C++?
... PODs,
enums are PODs
a const or volatile POD is a POD.
a class, struct or union of PODs is a POD provided that all non-static data members are public, and it has no base class and no constructors, destructors, or virtual methods. Static members don't stop something being a POD under this rule. This...
Run php script as daemon process
... service:
[Unit]
Description=My PHP Daemon Service
#May your script needs MySQL or other services to run, eg. MySQL Memcached
Requires=mysqld.service memcached.service
After=mysqld.service memcached.service
[Service]
User=root
Type=simple
TimeoutSec=0
PIDFile=/var/run/myphpdaemon.pid
ExecStart=/u...