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SQL to find the number of distinct values in a column
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Be aware that Count() ignores null values, so if you need to allow for null as its own distinct value you can do something tricky like:
select count(distinct my_col)
+ count(distinct Case when my_col is null then 1 else null end)
from my_table
/
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What's the reason for “Error:Cannot determine Java VM executable in selected JDK”?
...is not updated accordingly when the Project SDK is changed, see SCL-10085. If you have the other JDK (1.7 in my example) generally configured, no error will occur, but the Project SDK will silently be changed back. Otherwise, this error occurs.
The problem can easily be resolved by manually editing...
Extracting hours from a DateTime (SQL Server 2005)
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DATEPART(HOUR, [date]) returns the hour in military time ( 00 to 23 )
If you want 1AM, 3PM etc, you need to case it out:
SELECT Run_Time_Hour =
CASE DATEPART(HOUR, R.date_schedule)
WHEN 0 THEN '12AM'
WHEN 1 THEN '1AM'
WHEN 2 THEN '2AM'
WHEN 3 THEN '3AM'
WHEN 4 THEN ...
使用 C++ 处理 JSON 数据交换格式 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ect;
const char* json_document = "{/"age/" : 26,/"name/" : /"huchao/"}";
if (!reader.parse(json_document, json_object))
return 0;
std::cout << json_object["name"] << std::endl;
std::cout << json_object["age"] << std::endl;
输出结果为：
"huchao"
26
可见，上述代码已...
Class JavaLaunchHelper is implemented in both. One of the two will be used. Which one is undefined [
... work without any problems using JDK 1.7.0_60 despite seeing the message.
If this issue is causing serious problems, here are a few things I would suggest:
Revert back to JDK 1.7.0_25 until a fix is added to the JDK.
Keep an eye on the bug report so that you are aware of any work being done on t...
%Like% Query in spring JpaRepository
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Helpful if we use something=:place and another like %:place% in query.
– hong4rc
Jul 10 at 2:31
add a commen...
JUnit tests pass in Eclipse but fail in Maven Surefire
...gt;
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.12</version>
<configuration>
<forkMode>always</forkMode>
</configuration>
</plugin>
Surefire param...
Getting all file names from a folder using C# [duplicate]
I wanted to know if it is possible to get all the names of text files in a certain folder.
7 Answers
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Getting rid of bullet points from
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What is the difference of doing ul#otis and #otis?
– PeeHaa
Nov 27 '11 at 23:05
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How to store Java Date to Mysql datetime with JPA
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be aware that if you choose this solution, your date will appear as a timestamp when fetched from db. It won't have the nice formatting 'yyyy-MM-dd....')
– jon
Aug 5 '16 at 18:52
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