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How do I delete a fixed number of rows with sorting in PostgreSQL?
...
You could try using the ctid:
DELETE FROM logtable
WHERE ctid IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly,...
Modifying a subset of rows in a pandas dataframe
...The df.A==0 expression creates a boolean series that indexes the rows, 'B' selects the column. You can also use this to transform a subset of a column, e.g.:
df.loc[df.A==0, 'B'] = df.loc[df.A==0, 'B'] / 2
I don't know enough about pandas internals to know exactly why that works, but the basic is...
Naming of ID columns in database tables
...!)and forget to change the alias in the join condition.
So you now have
select t1.field1, t2.field2, t3.field3
from table1 t1
join table2 t2 on t1.id = t2.table1id
join table3 t3 on t1.id = t3.table2id
when you meant
select t1.field1, t2.field2, t3.field3
from table1 t1
join table2 t2 on t1...
Why there is no ForEach extension method on IEnumerable?
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Couldn't you just use Select instead of your Apply method? It seems to me that applying an action to each element and yielding it is exactly what Select does. E.g. numbers.Select(n => n*2);
– rasmusvhansen
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What is a stored procedure?
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CREATE PROCEDURE Users_GetUserInfo
@login nvarchar(30)=null
AS
SELECT * from [Users]
WHERE ISNULL(@login,login)=login
A benefit of stored procedures is that you can centralize data access logic into a single place that is then easy for DBA's to optimize. Stored procedures also have...
Stash only one file out of multiple files that have changed with Git?
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You can also use git stash save -p "my commit message". This way you can select which hunks should be added to stash, whole files can be selected as well.
You'll be prompted with a few actions for each hunk:
y - stash this hunk
n - do not stash this hunk
q - quit; do not stash this hun...
How do I see what character set a MySQL database / table / column is?
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Here's how I'd do it -
For Schemas (or Databases - they are synonyms):
SELECT default_character_set_name FROM information_schema.SCHEMATA
WHERE schema_name = "schemaname";
For Tables:
SELECT CCSA.character_set_name FROM information_schema.`TABLES` T,
information_schema.`COLLATION_CHAR...
What can I do with a moved-from object?
...should be a separate question, but does that mean: if I have a string with char* buffer; and int length; members, then my move constructor/assignment must swap (or set) the value of both? Or would it be OK, if the length was unspecified (meaning that empty and size return meaningless values)?
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Tools to selectively Copy HTML+CSS+JS From A Specific Element of DOM [closed]
... well. The problem was that we were taking only a part of the HTML and CSS selectors that were matching in the context of the whole document, which were not matching anymore in the context of an HTML snippet. Since parsing and modifying selectors didn't seem like a good idea, I gave up on this attem...
What is so bad about singletons? [closed]
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I disagree with you. Since comments are allowed only 600 chars, I have written a Blog Post to comment on this, please see the link below. jorudolph.wordpress.com/2009/11/22/singleton-considerations
– Johannes Rudolph
Nov 22 '09 at 14:35
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