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How to drop a table if it exists?
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Is it correct to do the following?
IF EXISTS(SELECT *
FROM dbo.Scores)
DROP TABLE dbo.Scores
No. That will drop the table only if it contains any rows (and will raise an error if the table does not exist).
Instead, for a permanent table you can use
I...
Find column whose name contains a specific string
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# select columns containing 'spike'
df.filter(like='spike', axis=1)
You can also select by name, regular expression. Refer to: pandas.DataFrame.filter
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Fixing “Lock wait timeout exceeded; try restarting transaction” for a 'stuck" Mysql table?
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You can check the currently running transactions with
SELECT * FROM `information_schema`.`innodb_trx` ORDER BY `trx_started`
Your transaction should be one of the first, because it's the oldest in the list. Now just take the value from trx_mysql_thread_id and send it the KILL ...
How do I set the size of Emacs' window?
... got the following in my .emacs:
(if (window-system)
(set-frame-height (selected-frame) 60))
You might also look at the functions set-frame-size, set-frame-position, and set-frame-width. Use C-h f (aka M-x describe-function) to bring up detailed documentation.
I'm not sure if there's a way to ...
How to apply two CSS classes to a single element
...To target elements that contain all of the specified classes, use this CSS selector (no space) (ref):
.c1.c2 {
}
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PostgreSQL: Difference between text and varchar (character varying)
... article does detailed testing to show that the performance of inserts and selects for all 4 data types are similar. It also takes a detailed look at alternate ways on constraining the length when needed. Function based constraints or domains provide the advantage of instant increase of the length c...
Specify pane percentage in tmuxinator project
...e preset layouts (such as main-vertical). From the man page:
In addition, select-layout may be used to apply a previously used layout -
the list-windows command displays the layout of each window in a form
suitable for use with select-layout. For example:
$ tmux list-windows
0: ks...
How to get Spinner value?
In Android, I am trying to get the selected Spinner value with a listener.
7 Answers
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Using 'starts with' selector on individual class names
...thought of using space in there. Can one use boolean operators in a jquery selector? Ideally, the above would be 'OR' to avoid the (rare and likely avoidable) case where there are more than one class staring with 'apple-'
– DA.
Feb 1 '10 at 17:12
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Why use the INCLUDE clause when creating an index?
...ot in the WHERE/JOIN/GROUP BY/ORDER BY, but only in the column list in the SELECT clause.
The INCLUDE clause adds the data at the lowest/leaf level, rather than in the index tree.
This makes the index smaller because it's not part of the tree
INCLUDE columns are not key columns in the index, so th...