大约有 40,000 项符合查询结果(耗时:0.0261秒) [XML]

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Right query to get the current number of connections in a PostgreSQL DB

...ires aren't equivalent. The equivalent version of the first one would be: SELECT sum(numbackends) FROM pg_stat_database; In that case, I would expect that version to be slightly faster than the second one, simply because it has fewer rows to count. But you are not likely going to be able to measu...
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WHERE vs HAVING

Why do you need to place columns you create yourself (for example select 1 as "number" ) after HAVING and not WHERE in MySQL? ...
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What's the purpose of SQL keyword “AS”?

...ynes Yes. Just concatenate (||) the columns and then give it an alias e.g. SELECT foo || bar AS foobar. – Rupert Madden-Abbott Dec 10 '18 at 14:26 ...
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Eclipse: All my projects disappeared from Project Explorer

...Do File->Import General->Existing Projects into Workspace Click the "Select root directory" field and browse to each subfolder in your workspace folder, and import. For me, this was very tedious, since I had several dozen projects in my workspace, but it's the only solution I found short of ...
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Android: create a popup that has multiple selection options

... Hello, can you also show how I can set actions for specific item selections? Example: I want to let the user change the app language by clicking one of those items (probably using if statement). – Arda Çebi Feb 7 '18 at 20:11 ...
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Dynamically select data frame columns using $ and a character value

...and some variable names stored in a character vector cols . When I try to select a variable from mtcars using a dynamic subset of cols , nether of these work ...
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jQuery - select all text from a textarea

...can I make it so when you click inside a textarea, its entire content gets selected? 6 Answers ...
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What's the best UI for entering date of birth? [closed]

What is the best method for date of birth selector? 24 Answers 24 ...
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Best way to unselect a in jQuery?

What is the best way, using jQuery, to elegantly unselect the option? 15 Answers 15 ...
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MySQL date format DD/MM/YYYY select query?

...ably just want to format the output date? then this is what you are after SELECT *, DATE_FORMAT(date,'%d/%m/%Y') AS niceDate FROM table ORDER BY date DESC LIMIT 0,14 Or do you actually want to sort by Day before Month before Year? ...