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Is there any performance gain in indexing a boolean field?
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It depends on the actual queries and the selectivity of the index/query combination.
Case A: condition WHERE isok = 1 and nothing else there:
SELECT *
FROM tableX
WHERE isok = 1
If the index is selective enough (say you have 1M rows and only 1k have isok = 1), ...
jquery how to empty input field
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On a related note, .val([]) can also unselect any selected option in select list... not so much with .val(''). Best thing about it is it's cross-browser support. P.S: This is an alternative to only other efficient cross-browser solution - $("select option").prop("...
Programmatically trigger “select file” dialog box
I have a hidden file input element. Is it possible to trigger its select file dialog box from a button's click event?
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How to select .NET 4.5.2 as a target framework in Visual Studio
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onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true,enableSnippets:true
});
}
});
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Compare dates in MySQL
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You can try below query,
select * from players
where
us_reg_date between '2000-07-05'
and
DATE_ADD('2011-11-10',INTERVAL 1 DAY)
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How to use greater than operator with date?
..._date with single quote causing it to become string, use backtick instead
SELECT * FROM `la_schedule` WHERE `start_date` > '2012-11-18';
SQLFiddle Demo
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Select random lines from a file
...e point is you can keep some lines in memory with shuffle to do the random selection of what to output. Sort is going to sort the entire file, regardless of what your needs are.
– Rubens
Sep 25 '14 at 2:01
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SQL “select where not in subquery” returns no results
...MySQL
There are three ways to do such a query:
LEFT JOIN / IS NULL:
SELECT *
FROM common
LEFT JOIN
table1 t1
ON t1.common_id = common.common_id
WHERE t1.common_id IS NULL
NOT EXISTS:
SELECT *
FROM common
WHERE NOT EXISTS
(
SELECT NULL
FROM ...
Maximum Year in Expiry Date of Credit Card
...orget that in most browsers you can still key in the number and it'll auto select.
– Kevin Wiskia
Mar 22 '11 at 19:44
1
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Convert text into number in MySQL query
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This should work:
SELECT field,CONVERT(SUBSTRING_INDEX(field,'-',-1),UNSIGNED INTEGER) AS num
FROM table
ORDER BY num;
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