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Computed / calculated / virtual / derived columns in PostgreSQL
...y as column?
The expression (looking like a column) is not included in a SELECT * FROM tbl, though. You always have to list it explicitly.
Can also be supported with a matching expression index - provided the function is IMMUTABLE. Like:
CREATE FUNCTION col(tbl) ... AS ... -- your computed expr...
Visual Studio hot keys change occasionally, specifically F6 vs Ctrl-Shift-B for building. WHY?
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This is because you might have selected "General Development Settings" as your default environment settings for your Visual Studio (which usually we do on the first launch of VS after installing it as it pops up a dialogue box to choose default environment...
Selectively revert or checkout changes to a file in Git?
... @Jan Do other version control systems' revert command allow you to select which changes within a file are reverted? Genuinely asking, as I only have experience with CVS and Git. In Git, git checkout -- path/to/file is a single command that reverts all changes in that file, but this is not th...
Xcode + remove all breakpoints
...l breakpoints.
In Xcode4 press CMD(⌘)+6, in Xcode3 press CMD(⌘)+ALT+B.
Select all breakpoints with CMD(⌘)+A and delete them, like deleting text, with backspace.
There's no step 3 :)
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Build unsigned APK file with Android Studio
...nu in the toolbar at the top (Open 'Edit Run/Debug configurations' dialog)
Select "Edit Configurations"
Click the "+"
Select "Gradle"
Choose your module as a Gradle project
In Tasks: enter assemble
Press Run
Your unsigned APK is now located in
ProjectName\app\build\outputs\apk
For detailed inf...
DataSet panel (Report Data) in SSRS designer is gone
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With a report (rdl) file selected in your solution, select View and then Report Data.
It is a shortcut of Ctrl+Alt+D.
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get list of pandas dataframe columns based on data type
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If you are just selecting columns by data type, then this answer is obsolete. Use select_dtypes instead
– Ted Petrou
Nov 3 '17 at 16:58
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Copy/duplicate database without using mysqldump
...the references, you can run the following to copy the data:
INSERT INTO x SELECT * FROM other_db.y;
If you're using MyISAM, you're better off to copy the table files; it'll be much faster. You should be able to do the same if you're using INNODB with per table table spaces.
If you do end up doin...
How to trim a string in SQL Server before 2017?
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SELECT LTRIM(RTRIM(Names)) AS Names FROM Customer
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Heroku Postgres - terminate hung query (idle in transaction)
...'s not desirable or not an option ...)
Find the PID by running this sql:
SELECT pid , query, * from pg_stat_activity
WHERE state != 'idle' ORDER BY xact_start;
(The query may need mending dependent of the version of postgres - eventually, just select * from pg_stat_activity). You'll find the ...