大约有 48,000 项符合查询结果（耗时：0.0593秒） [XML]
COUNT DISTINCT with CONDITIONS
...bination of Tag & Entry ID when [Entry Id]>0
select count(distinct(concat(tag,entryId)))
from customers
where id>0
In the output it will display the count of unique values
Hope this helps
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Count the items from a IEnumerable without iterating?
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...in cases where things like Enumerable.Concat are used to combine a large collection which knows a lot about itself with a small one that doesn't.
– supercat
Feb 19 '15 at 20:16
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How does the String class override the + operator?
...ls of the string conversion context.
15.18.1.
Optimization of String Concatenation :
An implementation may choose to perform conversion and concatenation
in one step to avoid creating and then discarding an intermediate
String object. To increase the performance of repeated string
conc...
How to get ID of the last updated row in MySQL?
...E footable
SET foo = 'bar'
WHERE fooid > 5
AND ( SELECT @uids := CONCAT_WS(',', fooid, @uids) );
SELECT @uids;
This will return a string with all the IDs concatenated by a comma.
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Java multiline string
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Furthermore, the first version will be automatically concatenated by the compiler, since all the strings are known at compile time. Even if the strings are not known at compile time, it's no slower than StringBuilder or String.format(). The only reason to avoid concatenation wi...
Convert array of integers to comma-separated string
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I am using .NET 4.5. I tried to concat the comma separated numbers with a string. I got an error saying "cannot convert string[] to char". So the earlier version worked flawlessly.
– Prasanth G
Jan 30 at 12:49
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Inno Setup for Windows service?
...ystem.Environment.UserInteractive)
{
string parameter = string.Concat(args);
switch (parameter)
{
case "--install":
ManagedInstallerClass.InstallHelper(new string[] { Assembly.GetExecutingAssembly().Location });
break;
...
Get current domain
... mostly importantly it includes the port number so that I do not need to concat it afterwards. phpinfo suggested by bsdnoobz helps me to find the right solution though.
– user1021364
Aug 8 '14 at 4:14
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Interview question: Check if one string is a rotation of other string [closed]
...nd s2 are of the same length. Then check to see if s2 is a substring of s1 concatenated with s1:
algorithm checkRotation(string s1, string s2)
if( len(s1) != len(s2))
return false
if( substring(s2,concat(s1,s1))
return true
return false
end
In Java:
boolean isRotation(String s1,St...
How can I get a resource “Folder” from inside my jar File?
...nput Stream will have all the files name from that dir. After that you can concat the dir path with each file name and call getResourceAsStream for each file in a loop.
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