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postgresql COUNT(DISTINCT …) very slow
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You can use this:
SELECT COUNT(*) FROM (SELECT DISTINCT column_name FROM table_name) AS temp;
This is much faster than:
COUNT(DISTINCT column_name)
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How to pass values between Fragments
... I tried step 5, That i'm calling listactivity from fragment and after selecting item from that activity, i want to come back in fragment with selected file name. But its not working, its giving me Nullpointer Exception at onCreateView. Any solution on this please? This is my question stackoverf...
What is the HTML tabindex attribute?
...ments support the tabindex attribute: anchor, area, button, input, object, select, and textarea. But the HTML5 spec, with accessibility in mind, allows all elements to be assigned tabindex.
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For example
<ul tabindex="-1">
<li tabindex="1"></li>
<li tabindex="2"><...
解决：ORA-00054:资源正忙,要求指定NOWAIT - 数据库(内核) - 清泛网 - 专注...
...删除
1：找出所有被锁的对象，定位出哪个回话占用
select l.session_id,o.owner,o.object_name from v$locked_object l,dba_objects o where l.object_id=o.object_id
结果：
session_id owner object_name
158 SA TEST_1
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对比想要创建的索引，定位哪些会话需要...
How to remove leading zeros from alphanumeric text?
...for start of input rather than start of line). The 0* means zero or more 0 characters (you could use 0+ as well). The replaceFirst just replaces all those 0 characters at the start with nothing.
And if, like Vadzim, your definition of leading zeros doesn't include turning "0" (or "000" or similar s...
How to sum up an array of integers in C#
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Point taken. Yet, the following saves 18 chars compared to your sample: foreach (int i in arr) sum += i;
– Jørn Schou-Rode
Mar 16 '10 at 11:44
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How to initialize all the elements of an array to any specific value in java
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[Incidentally, memset in C or C++ is only of any real use for arrays of char.]
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What is the most appropriate way to store user settings in Android application
... protected static final String UTF8 = "utf-8";
private static final char[] SEKRIT = ... ; // INSERT A RANDOM PASSWORD HERE.
// Don't use anything you wouldn't want to
// get out there if someone deco...
Sort a list from another list IDs
...; source,
IEnumerable<TId> order,
Func<T, TId> idSelector)
{
var lookup = source.ToDictionary(idSelector, t => t);
foreach (var id in order)
{
yield return lookup[id];
}
}
Is a generic extension for what you want.
You could use the extension li...
Eclipse: Error “.. overlaps the location of another project..” when trying to create new project
...r_src.
Right-click on the project explorer and import an existing project, select C:\Users\Martin\Java\Counter\ as your root directory. If Eclipse sees a project, you will be able to import it.
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