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How does one reorder columns in a data frame?
...
You can also use the subset function:
data <- subset(data, select=c(3,2,1))
You should better use the [] operator as in the other answers, but it may be useful to know that you can do a subset and a column reorder operation in a single command.
Update:
You can also use the select...
Count the number of occurrences of a string in a VARCHAR field?
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This should do the trick:
SELECT
title,
description,
ROUND (
(
LENGTH(description)
- LENGTH( REPLACE ( description, "value", "") )
) / LENGTH("value")
) AS count
FROM <tab...
SQL statement to get column type
...
Using SQL Server:
SELECT DATA_TYPE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME = 'yourTableName' AND
COLUMN_NAME = 'yourColumnName'
share
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Function vs. Stored Procedure in SQL Server
...-----------+----------------------------------------+
| We can't use SP in SELECT/ | We can use UDF in SELECT/ WHERE/ |
| WHERE/ HAVING statement. | HAVING statement. |
+---------------------------------+----------------------------------------+
| We can use ex...
Get first day of week in SQL Server
...in that there should be some sensible logic built in to round up or down:
SELECT DATEDIFF(YEAR, '2010-01-01', '2011-12-31');
SELECT DATEDIFF(YEAR, '2010-12-31', '2011-01-01');
To answer how to get a Sunday:
If you want a Sunday, then pick a base date that's not a Monday but rather a Sunday. For ...
MySQL - How to select data by string length
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select LENGTH('Ö'); results 2!! András Szepesházi's answer is the correct one!
– fubo
Oct 24 '13 at 13:59
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How to generate Class Diagram (UML) on Android Studio (IntelliJ Idea)
...ight click on the folder containing the classes you want to visualize, and select Add to simpleUML Diagram.
That's it; you have you fancy class diagram generated from your code!
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|
improve thi...
How to change an Eclipse default project into a Java project
.... Taking a backup is very recommended!
How to do it just using Eclipse?
Select project.
Open the project properties through Project -> Properties.
Go to "Targetted Runtimes" and add the proper runtime. Click APPLY.
Go to "Project Facets" and select the JAVA facet which has appeared due to step...
Count(*) vs Count(1) - SQL Server
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The optimizer recognizes it for what it is: trivial.
The same as EXISTS (SELECT * ... or EXISTS (SELECT 1 ...
Example:
SELECT COUNT(1) FROM dbo.tab800krows
SELECT COUNT(1),FKID FROM dbo.tab800krows GROUP BY FKID
SELECT COUNT(*) FROM dbo.tab800krows
SELECT COUNT(*),FKID FROM dbo.tab800krows GROU...
How can I find which tables reference a given table in Oracle SQL Developer?
... has such option). The following SQL is that one used by PLSQL Developer:
select table_name, constraint_name, status, owner
from all_constraints
where r_owner = :r_owner
and constraint_type = 'R'
and r_constraint_name in
(
select constraint_name from all_constraints
where constraint_type in ...