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MySql Table Insert if not exist otherwise update
... re-written using the proper INSERT ... ON DUPLICATE KEY UPDATE syntax for MySQL:
INSERT INTO AggregatedData (datenum,Timestamp)
VALUES ("734152.979166667","2010-01-14 23:30:00.000")
ON DUPLICATE KEY UPDATE
Timestamp=VALUES(Timestamp)
...
Possible to do a MySQL foreign key to one of two possible tables?
...ut logical XOR is not standard SQL and is not supported by all SQL brands. MySQL has it, but PostgreSQL does not. Oracle has it, but Microsoft does not until 2016. And so on.
– Bill Karwin
Aug 19 '15 at 15:09
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Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' (38)
I am having a big problem trying to connect to mysql. When I run:
41 Answers
41
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Optimal way to concatenate/aggregate strings
...com/en-us/sql/t-sql/functions/string-agg-transact-sql
GROUP_CONCAT() in MySQL
http://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_group-concat
(Thanks to @Brianjorden and @milanio for Azure update)
Example Code:
select Id
, STRING_AGG(Name, ', ') Names
from Demo
group by I...
PDOException SQLSTATE[HY000] [2002] No such file or directory
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The error message indicates that a MySQL connection via socket is tried (which is not supported).
In the context of Laravel (artisan), you probably want to use a different / the correct environment. Eg: php artisan migrate --env=production (or whatever enviro...
Is there a REAL performance difference between INT and VARCHAR primary keys?
...e performance difference between using INT vs. VARCHAR as a primary key in MySQL? I'd like to use VARCHAR as the primary key for reference lists (think US States, Country Codes) and a coworker won't budge on the INT AUTO_INCREMENT as a primary key for all tables.
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How to shrink/purge ibdata1 file in MySQL
I am using MySQL in localhost as a "query tool" for performing statistics in R, that is, everytime I run a R script, I create a new database (A), create a new table (B), import the data into B, submit a query to get what I need, and then I drop B and drop A.
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MySQL show status - active or total connections?
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Connections
The number of connection attempts (successful or not) to the MySQL server.
You can see the number of active connections either through the Threads_connected status variable:
Threads_connected
The number of currently open connections.
mysql> show status where `variable_name` = 'Th...
常用Git命令汇总 - 开源 & Github - 清泛网 - 专注C/C++及内核技术
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#改变暂存区的修改（其实是重置HEAD，将指定版本库的内容状态去覆盖暂存区，从而达到暂存区的改变）
git reset <file> #从暂存区恢复到工作区（不指定版本id，则默认为最后一次提交的版本id）
git r...
实战做项目如何选择开源许可协议（一）-了解协议 - 开源 & Github - 清泛网...
实战做项目如何选择开源许可协议（一）-了解协议opensource_permission目前国内开源项目正在逐渐升温，中国也开始有不少优秀的开源项目突显出来。在大家摩拳擦掌准备加入开源大军时，也要知道这个圈子里的规则。...目前国内...