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How to check if a column exists in a SQL Server table?
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SQL Server 2005 onwards:
IF EXISTS(SELECT 1 FROM sys.columns
WHERE Name = N'columnName'
AND Object_ID = Object_ID(N'schemaName.tableName'))
BEGIN
-- Column Exists
END
Martin Smith's version is shorter:
IF COL_LENGTH('schemaName.tabl...
IntelliJ IDEA way of editing multiple lines
...ossibility to edit multiple lines.
Use:
Alt + Shift + Mouse click
for selection. More about this new improvement in IntelliJ blogpost here. Very useful feature.
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Replacement for “rename” in dplyr
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The next version of dplyr will support an improved version of select that also incorporates renaming:
> mtcars2 <- select( mtcars, disp2 = disp )
> head( mtcars2 )
disp2
Mazda RX4 160
Mazda RX4 Wag 160
Datsun 710 108
Hornet 4 Drive 258
H...
How to drop column with constraint?
...ing of constraints script:
DECLARE @sql NVARCHAR(MAX)
WHILE 1=1
BEGIN
SELECT TOP 1 @sql = N'alter table tbloffers drop constraint ['+dc.NAME+N']'
from sys.default_constraints dc
JOIN sys.columns c
ON c.default_object_id = dc.object_id
WHERE
dc.parent_object_id = OBJ...
How do I check if an index exists on a table field in MySQL?
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Try:
SELECT * FROM information_schema.statistics
WHERE table_schema = [DATABASE NAME]
AND table_name = [TABLE NAME] AND column_name = [COLUMN NAME]
It will tell you if there is an index of any kind on a certain column wi...
Why do we always prefer using parameters in SQL statements?
I am very new to working with databases. Now I can write SELECT , UPDATE , DELETE , and INSERT commands. But I have seen many forums where we prefer to write:
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Git in Visual Studio - add existing project?
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Just right click on your solution and select Add to source control. Then select Git.
Now your projects has been added to a local source control. Right click on one of your files and select Commit.
Then enter a commit message and select Commit. Then select Sync ...
Joining three tables using MySQL
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Simply use:
select s.name "Student", c.name "Course"
from student s, bridge b, course c
where b.sid = s.sid and b.cid = c.cid
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How to copy a selection to the OS X clipboard
I have an area selected in Vim. How can I copy it into the OS X clipboard?
27 Answers
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Select multiple columns in data.table by their numeric indices
How can we select multiple columns using a vector of their numeric indices (position) in data.table ?
5 Answers
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