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Find difference between timestamps in seconds in PostgreSQL
...
Try:
SELECT EXTRACT(EPOCH FROM (timestamp_B - timestamp_A))
FROM TableA
Details here: EXTRACT.
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Why there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT clause?
...pdated) values(null, null);
Query OK, 1 row affected (0.06 sec)
mysql> select * from t5;
+----+---------------------+---------------------+
| id | stamp_created | stamp_updated |
+----+---------------------+---------------------+
| 2 | 2009-04-30 09:44:35 | 2009-04-30 09:44:35 |
+...
Show data on mouseover of circle
...and you don't need the mousehandler. The code would be something like
vis.selectAll("circle")
.data(datafiltered).enter().append("svg:circle")
...
.append("svg:title")
.text(function(d) { return d.x; });
If you want fancier tooltips, you could use tipsy for example. See here for an ex...
Why does installing Nokogiri on Mac OS fail with libiconv is missing?
...ed to install xCode command tools to allow you to install libiconv.
xcode-select --install
then install a newer version of libiconv
brew install libiconv
then install your gem
gem install nokogiri -- --with-iconv-dir=/usr/local/Cellar/libiconv/1.14
...
How to format an inline code in Confluence?
... {{example}}.
If you're using Confluence 4.x or higher, you can also just select the "Preformatted" option from the paragraph style menu. Please note that will apply to the entire line.
Full reference here.
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C# 通过代码安装、卸载、启动、停止服务 - .NET(C#) - 清泛IT论坛，有思想、有深度
#region Windows服务控制区
#region 安装服务
private void InstallService(string filepath, string serviceName)
{
try
&nb...
How can I view the shared preferences file using Android Studio?
...in. 4. Start Android Emulator (in my case API 24) 5. Launch stetho-sample (select it from run configuration menu next to green arrow 6. On your PC open latest Chrome browser 7. go by chrome://inspect address 8. chose your emulator in list. 9. In opened window go to Resources tab. 10. Find your share...
How to call a stored procedure from Java and JPA
...s (
postId IN NUMBER,
commentCount OUT NUMBER )
AS
BEGIN
SELECT COUNT(*) INTO commentCount
FROM post_comment
WHERE post_id = postId;
END;
You can call it from JPA as follows:
StoredProcedureQuery query = entityManager
.createStoredProcedureQuery("count_comments"...
String concatenation in MySQL
...most DBMSs use of + or || for concatenation. It uses the CONCAT function:
SELECT CONCAT(first_name, " ", last_name) AS Name FROM test.student
As @eggyal pointed out in comments, you can enable string concatenation with the || operator in MySQL by setting the PIPES_AS_CONCAT SQL mode.
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Does the join order matter in SQL?
...t matter. The queries will return same results, as long as you change your selects from SELECT * to SELECT a.*, b.*, c.*.
For (LEFT, RIGHT or FULL) OUTER joins, yes, the order matters - and (updated) things are much more complicated.
First, outer joins are not commutative, so a LEFT JOIN b is no...