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How do I find duplicates across multiple columns?

... Duplicated id for pairs name and city: select s.id, t.* from [stuff] s join ( select name, city, count(*) as qty from [stuff] group by name, city having count(*) > 1 ) t on s.name = t.name and s.city = t.city ...
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Browse the files created on a device by the iOS application I'm developing, on workstation?

...in the bottom half of the window. In Xcode 6, go to Window -> Devices, select the device, select the app name under Installed Apps, click the settings gearbox, then select Download container.... In finder, double finger tap the package and select Show package contents. ...
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How to use GROUP_CONCAT in a CONCAT in MySQL

... select id, group_concat(`Name` separator ',') as `ColumnName` from ( select id, concat(`Name`, ':', group_concat(`Value` separator ',')) as `Name` from mytbl group by id, `Name` ) tbl group by id; ...
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How to get the first and last date of the current year?

... SELECT DATEADD(yy, DATEDIFF(yy, 0, GETDATE()), 0) AS StartOfYear, DATEADD(yy, DATEDIFF(yy, 0, GETDATE()) + 1, -1) AS EndOfYear The above query gives a datetime value for midnight at the beginning of December 31. This ...
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How to create an installer for a .net Windows Service using Visual Studio

...out dragging stuff from the toolbox. Then right click on the gray area and select add installer. This will add an installer project file to your project. Then you will have 2 components on the design view of the ProjectInstaller.cs (serviceProcessInstaller1 and serviceInstaller1). You should then se...
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Calculate difference between two datetimes in MySQL

... USE TIMESTAMPDIFF MySQL function. For example, you can use: SELECT TIMESTAMPDIFF(SECOND, '2012-06-06 13:13:55', '2012-06-06 15:20:18') In your case, the third parameter of TIMSTAMPDIFF function would be the current login time (NOW()). Second parameter would be the last login time, w...
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PostgreSQL - max number of parameters in “IN” clause?

... explain select * from test where id in (values (1), (2)); QUERY PLAN Seq Scan on test (cost=0.00..1.38 rows=2 width=208) Filter: (id = ANY ('{1,2}'::bigint[])) But if try 2nd query: explain select * from test where id = an...
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What are the most useful Intellij IDEA keyboard shortcuts? [closed]

... These are some of my most used keyboard short cuts Syntax aware selection in the editor selects a word at the caret and then selects expanding areas of the source code. For example, it may select a method name, then the expression that calls this method, then the whole statement, then the...
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Unbound classpath container in Eclipse

... or 4. goto Properties -> Java Build Path -> Libraries Tab -> Select the erroneous system library -> Edit (On the right) -> Select alternate JRE -> Finish. – Rajkiran Jun 26 '14 at 12:11 ...
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Cannot ping AWS EC2 instance

...ICMP rule Protocol: Echo Request Port: N/A Source: your choice (I would select Anywhere to be able to ping from any machine) share | improve this answer | follow ...