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MYSQL OR vs IN performance
...for future Googlers. Total count of returned results is 7264 out of 10000
SELECT * FROM item WHERE id = 1 OR id = 2 ... id = 10000
This query took 0.1239 seconds
SELECT * FROM item WHERE id IN (1,2,3,...10000)
This query took 0.0433 seconds
IN is 3 times faster than OR
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App Inventor 2 项目合并工具 AIMerge · App Inventor 2 中文网
... CountDownScreen1 project, then clicking on the “Project” dropdown and selecting “Export selected project (.aia) to my computer”. Figure 4 shows how to select a project and where to click to download the project.
Figure 4: Steps to download the CountDownScreen1 project
Developer 2 Work I...
How do I alter the position of a column in a PostgreSQL database table?
... tablename (column defs go here);
insert into tablename (col1, col2, col3) select col1, col2, col3 from oldtable;
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Rename package in Android Studio
...n:
In your Project pane, click on the little gear icon ( )
Uncheck / De-select the Compact Empty Middle Packages option
Your package directory will now be broken up in individual directories
Individually select each directory you want to rename, and:
Right-click it
Select Refactor
Click o...
Switching between GCC and Clang/LLVM using CMake
...sudo update-alternatives --config c++
Will print something like this:
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/bin/g++ 20 auto mode
1 /usr/bin/clang++ 10 manual mode
2 ...
Removing transforms in SVG files
...ltogether without creating another transform attributes
Go to Edit -> Select All in All Layers
Go to Object -> Transform
In Transform panel
Uncheck Relative move and check Apply to each object separately
Set Horizontal and Vertical values according to your needs and click Apply
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How to find the mysql data directory from command line in windows
... the following command line:
mysql -s -N -uUSER -p information_schema -e 'SELECT Variable_Value FROM GLOBAL_VARIABLES WHERE Variable_Name = "datadir"'
The command will select the value only from mysql's internal information_schema database and disables the tabular output and column headers.
Outp...
Is there a way to call a stored procedure with Dapper?
...:
DECLARE @output int
EXEC <some stored proc> @i = @output OUTPUT
SELECT @output AS output1
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ORACLE 常用日期函数 - ORACLE - 清泛IT论坛，有思想、有深度
...日期。如果给出一负数，返回值日期之前几个月日期。
select add_months(to_date('20150201','yyyymmdd'), -1) from dual
结果：2015/1/1
相应的，加减天数add_days函数是不存在的，直接用+、-即可，例如：
select to_date('20150201','yyyymmdd')+1 from dual
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Eclipse fonts and background color
...→ General → Editors → Text Editors
Browse Appearance color options
Select background color options, uncheck default, change to black
Select background color options, uncheck default, change to colour of choice
To change text colours
Open Java → Editor → Syntax Colouring
Select ele...