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Rank function in MySQL
...NSI standard SQL query for my requirement. Please help me to convert it to MySQL .
11 Answers
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What's faster, SELECT DISTINCT or GROUP BY in MySQL?
...doesn't have to sort the output, and GROUP BY by default does. However, in MySQL even a DISTINCT+ORDER BY might still be faster than a GROUP BY due to the extra hints for the optimizer as explained by SquareCog.
– rustyx
Jan 25 '15 at 15:03
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How big can a MySQL database get before performance starts to degrade
At what point does a MySQL database start to lose performance?
15 Answers
15
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Reference - What does this error mean in PHP?
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Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given
First and foremost:
Please, don't use mysql_* functions in new code. They are no longer maintained and are officially deprecated. See the red box? Lea...
JAVA线程池管理及分布式HADOOP调度框架搭建 - 人工智能(AI) - 清泛IT社区，...
...了的东西，比如tomcat里的servlet就是线程，没有线程我们如何提供多用户访问呢？不过很多刚开始接触线程的开发攻城师却在这个上面吃了不少苦头。怎么做一套简便的线程开发模式框架让大家从单线程开发快速转入多线程开发...
MySQL order by before group by
...pand on my comments about using a subquery to accurate return this data.
MySQL does not force you to GROUP BY every column that you include in the SELECT list. As a result, if you only GROUP BY one column but return 10 columns in total, there is no guarantee that the other column values which bel...
How to DROP multiple columns with a single ALTER TABLE statement in SQL Server?
...DROP { [ CONSTRAINT ] constraint_name | COLUMN column } [ ,...n ]
For MySQL:
ALTER TABLE TableName
DROP COLUMN Column1,
DROP COLUMN Column2;
or like this1:
ALTER TABLE TableName
DROP Column1,
DROP Column2;
1 The word COLUMN is optional and can be omitted, except for RENAME...
MySQL select where column is not empty
In MySQL, can I select columns only where something exists?
13 Answers
13
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SQL Server equivalent of MySQL's NOW()?
I'm a MySQL guy working on a SQL Server project, trying to get a datetime field to show the current time. In MySQL I'd use NOW() but it isn't accepting that.
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'0000-00-00 00:00:00' can not be represented as java.sql.Timestamp error
...can use this JDBC URL directly in your data source configuration:
jdbc:mysql://yourserver:3306/yourdatabase?zeroDateTimeBehavior=convertToNull
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