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Fastest way to count exact number of rows in a very large table?
I have come across articles that state that SELECT COUNT(*) FROM TABLE_NAME will be slow when the table has lots of rows and lots of columns.
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SQL Server - Return value after INSERT
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No need for a separate SELECT...
INSERT INTO table (name)
OUTPUT Inserted.ID
VALUES('bob');
This works for non-IDENTITY columns (such as GUIDs) too
share
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Kill a postgresql session/connection
...user to use this function. This works on all operating systems the same.
SELECT
pg_terminate_backend(pid)
FROM
pg_stat_activity
WHERE
-- don't kill my own connection!
pid <> pg_backend_pid()
-- don't kill the connections to other databases
AND datname = 'database...
Dynamic Sorting within SQL Stored Procedures
...eing duplicated twice in the order by, and is a little more readable IMO:
SELECT
s.*
FROM
(SELECT
CASE @SortCol1
WHEN 'Foo' THEN t.Foo
WHEN 'Bar' THEN t.Bar
ELSE null
END as SortCol1,
CASE @SortCol2
WHEN 'Foo' THEN t.Foo
WHEN 'Bar' THEN t.Bar
ELSE...
Force CloudFront distribution/file update
...Click on Blank Function (custom)
Step 3
Click on empty (stroked) box and select S3 from combo
Step 4
Select your Bucket (same as for CloudFront distribution)
Step 5
Set an Event Type to "Object Created (All)"
Step 6
Set Prefix and Suffix or leave it empty if you don't know what it is.
Step ...
How to select label for=“XYZ” in CSS?
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The selector would be label[for=email], so in CSS:
label[for=email]
{
/* ...definitions here... */
}
...or in JavaScript using the DOM:
var element = document.querySelector("label[for=email]");
...or in JavaScript using...
Get table name by constraint name [duplicate]
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SELECT owner, table_name
FROM dba_constraints
WHERE constraint_name = <<your constraint name>>
will give you the name of the table. If you don't have access to the DBA_CONSTRAINTS view, ALL_CONSTRAINTS or US...
Freezing Row 1 and Column A at the same time
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Select cell B2 and click "Freeze Panes" this will freeze Row 1 and Column A.
For future reference, selecting Freeze Panes in Excel will freeze the rows above your selected cell and the columns to the left of your selected ce...
Use a list of values to select rows from a pandas dataframe [duplicate]
...andas.pydata.org/pandas-docs/stable/… for more details. A sort after the selection is needed.
– Wouter Overmeire
Aug 18 '14 at 15:16
1
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Select Pandas rows based on list index
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For large datasets, it is memory efficient to read only selected rows via the skiprows parameter.
Example
pred = lambda x: x not in [1, 3]
pd.read_csv("data.csv", skiprows=pred, index_col=0, names=...)
This will now return a DataFrame from a file that skips all rows except 1 and ...