My data has a column classification that has about 10 different relevant classes:  ('CO', 'CO01','CR', 'CR01', 'CR06', 'CR07', 'CR08', 'CO01GV', 'CO01LG') and like 'CI%'   How do I create a new column containing all these classes whenever it is applid?  My query looks like this:  select parent_uprn, count(*) address_count, st_centroid(ST_Union(geom)) geom  from pedro_test.mbus_raw where parent_uprn is not null group by parent_uprn   I need the classification column containing all of the classifications in each group, so that I can later query and sort groups accordingly  edit: Okay tried string_agg as suggested and it worked, however the rows are for example CO CO CO CO CO CO01, instead of just being CO CO01
I am looking for a way to concatenate the strings of a field within a group by query. So for example, I have a table:  ID   COMPANY_ID   EMPLOYEE 1    1            Anna 2    1            Bill 3    2            Carol 4    2            Dave   and I wanted to group by company_id to get something like:  COMPANY_ID   EMPLOYEE 1            Anna, Bill 2            Carol, Dave   There is a built-in function in mySQL to do this
Excel Date to String conversion How to make existing public files private? How can I redirect the user from one page to another using jQuery or pure JavaScript? Ubuntu in VirtualBox wants to install on every boot Can HTML checkboxes be set to readonly? I found there are so much excellent answer to questions about how to product high quality typesetting output. But I wonder how to save ink with LaTeX. What we need to think about to manage cost. page layout or something else? What happens when I hover over a link in Chrome? Sometimes you see a video of a fan or a propeller spinning very fast, and the apparent rotation is distorted. The fan can appear to be moving in the opposite direction of rotation, or even stationary. This optical illusion is known as the wagon-wheel effect. If I understand correctly, this occurs because the camera framerate is slower than the frequency at which the fan makes one rev, so stroboscopic effects should be expected.   Does the wagon-wheel effect occur only in videos, or can we observe it just with the eye? Can someone help me figure out the big-O for the recurrence relation $T(n) = T(n^{1/2}) + 1$?  I didn't think the master theorem would work since it requires $T(n) = T(n/b)$... to have $b$ as a constant. I was wondering if anyone could shed some light on a method to approach this problem? (not looking for a solution) I have a question about notation specifically square brackets $[$ and round brackets $($.  My textbook doesn't explain any of this and I cannot find a reliable source online to confirm the difference.  So my question is: What is the difference between round brackets and square brackets in terms of notation in Field Theory? For example, I see $F(x)$ and $F[x]$ in my textbook and I've always assumed they were the same thing. But apparently they're not. Is there ever a time they're the same?  I wanted to know the difference, it may be a silly question but it's something I want to make sure I understand. If I have a 18-55mm lens, is there a point in buying a 35mm prime lens? I have the Nikon kit lens that came with a D5100 — the kit lens is  . I was thinking of getting a fast lens and I am looking to buy the .  Should I consider 35mm or instead buy a 55-200mm for better range? Prove that $\frac{1}{\sin^2 z } = \sum\limits_{n= -\infty} ^ {+\infty} \frac{1}{(z-\pi n)^2} $ How to make nautilus forget saved password? I am browsing Shared folders on a Windows network through Samba.  When I first opened a system on the network I was asked for a login username, password and I checked the save-password setting. Now the shared folder opens directly without asking for authentication.  I want to browse the folder using a different user which has more access rights. How should I do that? I want to set up a diary that compiles in two different orders: One is work by day, the other is work by project according to tags I give to the particular chunks of work I did each day.   For example, I write my diary as usual in work by day form:  2/2/15  -- bought a new screwdriver (tag: car maintainence)   -- scetched my plan for world domination (tag: world domination)  3/4/15  -- started studying physics (tag: world domination)  -- finished tax declaraction (tag: burocracy)   Compiling by project would yield tags as sections:  car maintainence    -- 2/2/15: bought a new screwdriver  world domination  -- 2/2/15: scetched my plan for world domination  -- 3/4/15: started studying physics  burocracy  -- 3/4/15: finished tax declaraction   I know this is pretty close to the literal programming paradigm the whole LaTex documentation follows: A code chunks in a document can be compiled to two different orders: For human understanding and for use by the machine. However, I want two human readable versions --say pdf-files-- as output. Is there some package that helps? Why multiple capacitors in parallel? Wondering why you would choose to use smaller capacitors in parallel vs one bigger one.  Here's an example:      Is this a component size and track width choice?  Thanks! Not an essential singularity The following is an old qualifying exam that I cannot solve:  Suppose $f$ is holomorphic on the punctured unit disk and $ \frac{f '}{f} $ has a simple pole at $0$.  Show that $f$ does not have an essential singularity at $0$. How can I protect my save data from casual hacking? What options are there for saving game data in a secure manner? I'm interested in solutions specifically tailored for C++.   I'm looking for something that is fast and easy to use. I'm only concerned about storing simple information such as   Which levels are and are not unlocked The user's score for each level   I'm curious again to know what's out there to use, any good libraries to use that give me nice, secure game data files that the average player can't mess with.   I just found  here which looks very nice, but it would be great to get some opinions on potential other libraries/options out there. What determines how much experience I get from a hearthstone match in play mode? Sometimes I win handily and get a little experience, sometimes I squeak out a victory and get a lot.  How is experience earned? Big O, how do you calculate/approximate it? Most people with a degree in CS will certainly know what . It helps us to measure how well an algorithm scales.   But I'm curious, how do you calculate or approximate the complexity of your algorithms? How to find out the variant of my Galaxy Nexus? There have been some Jelly Bean updates for Galaxy Nexus, but most of these are specific to a certain variant of the Nexus. How can I easily find out which variant I have?