What is the error “Every derived table must have its own alias” in MySQL?

What is the error “Every derived table must have its own alias” in MySQL?

I am running this query on MySQLSELECT ID FROM ( SELECT ID, msisdn FROM ( SELECT * FROM TT2 ));and it is giving this error: Every derived table must have its own alias. What's causing this error? 1:Every derived table (A

Delete commits from a branch in Git

Delete commits from a branch in Git

I would like to know how to delete a commit.By "delete", I mean it is as if I didn't make that commit, and when I do a push in the future, my changes will not push to the remote branch.I read git help, and I think the command I should use i

JavaScript OR (||) variable assignment explanation

JavaScript OR (||) variable assignment explanation

Given this snippet of JavaScript...var a;var b = null;var c = undefined;var d = 4;var e = 'five';var f = a || b || c || d || e;alert(f); // 4Can someone please explain to me what this technique is called (my best guess is in the title of th

Why is there an unexplainable gap between these inline-block div elements?

Why is there an unexplainable gap between these inline-block div elements?

I have two inline-block div elements, that are the same, positioned next to eachother. However there seems to be a mysterious space of 4 pixels between the two divs despite the margin being set to 0. There are no parent divs effecting them

Is segmentation fault actual undefined behavior when we refer to a non-static data-member

Is segmentation fault actual undefined behavior when we refer to a non-static data-member

I had read the following rule and I've been trying to write an example, which reflects one.The rule is from 3.8/5 N3797: Before the lifetime of an object has started but after the storage which the object will occupy has been allocated or

How to navigate in JSF? How to make URL reflect current page (and not previous one)

How to navigate in JSF? How to make URL reflect current page (and not previous one)

I am currently learning JSF and was rather amazed and puzzled when I realized that whenever we use , the standard behavior of JSF is to always show me the URL of the previous page in the browser, as opposed to the URL of the current

How can I make Bootstrap columns all the same height?

How can I make Bootstrap columns all the same height?

I'm using Bootstrap. How can I make three columns all the same height?Here is a screenshot of the problem. I would like the blue and red columns to be the same height as the yellow column. Here is the code:

Is an array name a pointer?

Is an array name a pointer?

Is an array's name a pointer in C?If not, what is the difference between an array's name and a pointer variable? 1:An array is an array and a pointer is a pointer, but in most cases array names are converted to pointers. A term often use

How to integrate a library that uses expression templates?

How to integrate a library that uses expression templates?

I would like to use the Eigen matrix library as the linear algebra engine in my program. Eigen uses expression templates to implement lazy evaluation and to simplify loops and calculations.For example:#includeint main(){ int size = 40; //

Difference between glOrthof and glViewPort

Difference between glOrthof and glViewPort

On OpenGL-ES i'm confused on what the difference is between setting glOrthof() glViewPort()GLU.gluOrtho2D()with it's respective parameters. Since I believe it's all setting the part you can see to the specified coordinates (width, height

How can I disable Django's csrf protection only in certain cases?

How can I disable Django's csrf protection only in certain cases?

I'm trying to write a site in Django where the API URLs are the same as user-facing URLs. But I'm having trouble with pages which use POST requests and CSRF protection. For example, if I have a page /foo/add I want to be able to send POST

Playing multiple byte arrays simultaneously in Java

Playing multiple byte arrays simultaneously in Java

How can you play multiple (audio) byte arrays simultaneously? This "byte array" is recorded by TargetDataLine, transferred using a server.What I've tried so farUsing SourceDataLine:There is no way to play mulitple streams using SourceDataLi

Zend Framework 2 - Multiple modules by URL

Zend Framework 2 - Multiple modules by URL

I'm currently using the ZendFrameworkSkeleton application from Git and am trying to utilize the module part of it to have a multitude of modules, changeable by URL like so:http://localhost/application/index/index/http://localhost/guestbook/

android phonegap camera and image uploading

android phonegap camera and image uploading

I have been trying to make this work, searched google and here since Friday.My ultimate goal is to be able take multiple pictures with a title and description for each and upload them to a server, then display on a web page.What I have so f

FirstName, LastName in SQL, too complex?

FirstName, LastName in SQL, too complex?

This SQL seems complex, is there an easier way to get FirstName, LastName when one or both of the fields can be NULL?SELECT COALESCE(LastName,'')+ CASE WHEN LastName+FirstName IS NOT NULL THEN ', ' END+ COALESCE(FirstName,'') AS

Spring MVC, generating a form backing object from a request?

Spring MVC, generating a form backing object from a request?

I am using Spring MVC 2.5, and I am trying to get a JSTL form object to load from a GET request. I have Hibernate POJOs as my backing objects.There is one page directing to another page with a class id (row primary key) in the request. The

Detecting iPhone mute switch in iOS 5

Detecting iPhone mute switch in iOS 5

I know that Apple does not provide a way to detect the state of the iPhone mute/silence switch in iOS 5. However, I have I tried a technique mentioned elsewhere to detect this by playing an audio file and measuring its runtime. However, ev

How to update an “array of objects” with Firestore?

How to update an “array of objects” with Firestore?

I'm currently trying Firestore, and I'm stuck at something very simple: "updating an array (aka a subdocument)".My DB structure is super simple. For example:proprietary: "John Doe"sharedWith: [ {who: "[email protected]", when:timestamp}

Python many-to-one mapping (creating equivalence classes)

Python many-to-one mapping (creating equivalence classes)

I have a project of converting one database to another. One of the original database columns defines the row's category. This column should be mapped to a new category in the new database.For example, let's assume the original categories ar

Custom ConfigurationSection to external .config

Custom ConfigurationSection to external .config

I know there is an easy way to move any "standard" config section to external file i.e.but what about a custom ConfigurationSection? .... Is there any similar way? 1:You can useHowever unlike appSettings file=..., you must put the

IQueryable vs. IEnumerable in the repository pattern , lazy loading

IQueryable vs. IEnumerable in the repository pattern , lazy loading

I have read some articles that state that IEnumerable used to mimic stored procedures or restrict your database. Lost lazy loading ability on the external provider.Where as IQueryable to give developers more flexibility. Lazy loading is the

How can I avoid flicker in a WPF fullscreen app?

How can I avoid flicker in a WPF fullscreen app?

I have a WPF application that is a fullscreen kiosk app. It's actually a pretty complicated app at this point, but here's some code that shows the basic idea. Essentially, whenever the user goes from one screen to the next, there's some s

SQLite - getting closest value

SQLite - getting closest value

I have SQLite database and I have in it certain column of type "double".I want to get a row that has in this column value closest to a specified one.For example, in my table I have:id: 1; value: 47id: 2; value: 56id: 3; value: 51And I want

How can I iterate over properties from a file?

How can I iterate over properties from a file?

All my projects and their versions are defined in a properties file like this:ProjectNameA=0.0.1ProjectNameB=1.4.2I'd like to iterate over all the projects, and use their names and versions in an Ant script.At present I read the entire file

Replace values of a numpy index array with values of a list

Replace values of a numpy index array with values of a list

Suppose you have a numpy array and a list:>>> a = np.array([1,2,2,1]).reshape(2,2)>>> aarray([[1, 2], [2, 1]])>>> b = [0, 10]I'd like to replace values in an array, so that 1 is replaced by 0, and 2 by 10.I found a similar problem her