Temp table lives after being explicitly dropped
Is it "legal" to CREATE and DROP #SomeTable more than once?
The keyboard on my laptop seems to be typing by itself:   It sometimes types characters like 134, whether by itself or when I hit certain keys. Repeating characters may appear unexpectedly. The system volume may change by itself, or windows like the Print dialog or Web browser may appear.   This can happen without any input or as I type, and may occur more often when certain keys are pressed. Sometimes, the keyboard fails to respond altogether. This is happening regardless of the software involved.  Is there a ghost in my keyboard—is my keyboard broken?  A sample of text from the keyboard might look like this (normal QWERTY...ASDF...ZXC... sequence is expected):   QWERTYUIOPASDF)(G@*HKLZXCVBN QWERTYIOPASDFGL!#ZXCVB13 QWERTYUIOPASDFGHJKLZXCVB!#N qwertyu41iopasdf19g13h28j113k4113zxcvb4n qwerty4u1iopasdf0g7h1jklzxcvb13m qwert13uuuuuuuuuuuuuuuiopasdf87091134ghhhhhhhhhhhhhhhhhhhhhhh13jk13zxcvb14      This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details. If $A=AB-BA$, is $A$ nilpotent? Correct way to use include and includeonly when writing a large document like a thesis I have a very large dataset and about 5% random values are missing. These variables are correlated with each other. The following example R dataset is just a toy example with dummy correlated data.  set.seed(123)  # matrix of X variable  xmat &lt;- matrix(sample(-1:1, 2000000, replace = TRUE), ncol = 10000) colnames(xmat) &lt;- paste ("M", 1:10000, sep ="") rownames(xmat) &lt;- paste("sample", 1:200, sep = "") #M variables are correlated   N &lt;- 2000000*0.05 # 5% random missing values  inds &lt;- round ( runif(N, 1, length(xmat)) ) xmat[inds] &lt;- NA  &gt; xmat[1:10,1:10]          M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 sample1  -1 -1  1 NA  0 -1  1 -1  0  -1 sample2   1  1 -1  1  0  0  1 -1 -1   1 sample3   0  0  1 -1 -1 -1  0 -1 -1  -1 sample4   1  0  0 -1 -1  1  1  0  1   1 sample5  NA  0  0 -1 -1  1  0 NA  1  NA sample6  -1  1  0  1  1  0  1  1 -1  -1 sample7  NA  0  1 -1  0  1 -1  0  1  NA sample8   1 -1 -1  1  0 -1 -1  1 -1   0 sample9   0 -1  0 -1  1 -1  1 NA  0   1 sample10  0 -1  1  0  1  0  0  1 NA   0   Is there a (best) way to impute missing values in this situation? Is the Random Forest algorithm helpful? Any working solution in R would be much appreciated.  Edits:  (1) Missing values are randomly distributed among the variables and samples.As number of variables is very large (here in the example - 10000), while the number of samples is small here in the above dummy example it is about 200. So when we look at any sample over all the variables (10000), there is high chances that there will be missing value at some variable - due to large number of variables. So just deleting the sample is not option.   (2) The variable can be treated both as quantitative or qualitative (binary) in the process of imputing. The only judgement is how well we can predict it (accuracy). So predictions like 0.98 instead of 1 might be acceptable rather 0 vs 1 or -1 vs 1. I might need to tradeoff between computing time and accuracy.   (3)  The issue I have thinking how overfitting can affect the results as the number of variables are large compared to number of samples.   (4) As the total quantity of missing values is about 5% and is random (not concentrated in any variables or samples as precaution was taken to remove the variables or samples that have very high missing values)   (5) Making data complete for analysis is first objective and accuracy is secondary. So not too sensitive to accuracy. Construction of a right triangle It's a high school level question which we can't seem to solve. Here it is:      Given $2$ lines, one of the length of the hypotenuse and the other with the length of the sum of the $2$ legs, construct with straightedge and compass the corresponding right triangle   I didn't make much progress. It seems that there's a theorem or a few basic facts about right triangles that I'm missing. What path do you suggest I take?  Thanks for your help. Why Oracle discontinued Oracle Java (JDK) Installer PPA? Optimizing a screenshot for adding in a document and printing I am looking to replicate black &amp; white maps in QGis, using hatching patterns and greyscales to indicate different categories of a continuous variable (example below).  It is possible/straightforward to do so in QGis? At first sight I only see color gradients and symbol fills.   ). SQL Query; Admin Log System; Foreign Keys; Retriving multiple rows form different tables at once Table A (users)  id     | name   | ip 52433    Yashas   1.1.1.1 512      Admin    5.6.7.8   Table B (admin_record)  id    | admin | time    | date    | reason | action  52433   512     2312352   1213213   Test     WARN   id is FOREIGN key  Table B keeps a log of all actions an administrator takes on his users. And the table A stores the account information of the users &amp; administrators.  I am trying to display a list of actions taken by a administrators on a user.   I want to write a query which gets me all the rows of table B where id = fixed number.  Here is what I want to display:  "Administrator1 [Name]" took action on "User Name" for "[Note]" on XX/XX/XXXX. "Administrator2 [Name]" took action on "User Name" for "[Note]" on XX/XX/XXXX. "Administrator3 [Name]" took action on "User Name" for "[Note]" on XX/XX/XXXX.   All I have is the user's id using which I need to obtain all the entries in the log along with the administrator names. I need to obtain the admin's name, users name and all the contents of table B related to a particular user in one single query. If possible, I want the to change the field name(not literally change, but want the SQL server to send the data with new field names to separate admin name &amp; user name) of the admin's name to admin_name and user's name as . I mean something like this  SELECT users.name AS admin_name WHERE users.id = %i  AND SELECT users.name AS user_name WHERE users.id = %i   (the query isn't correct,it us just an example to show what I am trying)  Progress so far:   SELECT player.name, player.ip, admin.name, record.date, record.time, record.action, record.reason FROM admin_record AS record JOIN users AS player ON player.id = record.id JOIN users AS admin ON admin.id = record.admin WHERE player.id=%i   where admin_record is table B &amp; users is table A. Where can I check which difficulty bracket I'm in? Supposedly DOTA 2 matchmaking is divided into brackets.  I want to know which difficulty bracket I'm in. How can I find this information? If I replace my main panel, will I need to fit AFCIs? This question is about whether "circuits" can be grandfathered if the breaker or panel is changed but the circuit is otherwise not disturbed.   Code is NEC 2017.  My existing main panel has plenty of ampacity but few spaces, and thus, is totally full.  I have several potential paths for an upgrade.    One involves fitting a subpanel and moving 4 circuits (2 double-stuff breakers) there, and adding circuits there.    The other involves outright replacing the main with a very fine 60 space main panel.  No more space problems!  But what happens with AFCI and GFCI requirements? If this were a new house,  nearly all my circuits would require it, but I am grandfathered.  Will the  "new main" scenario void the grandfathering and require that nearly all circuits be upgraded to that protection?   Or can I just move over my old breakers and call it good? How many of Trelawney's prophecies have come true? Sort and display directory list alphabetically using opendir() in php When I install a simple program it often uses make &amp;&amp; make install and doesn't often even have an uninstall target.  If I wish to upgrade a program, is it standard protocol to assume it just rewrites seamlessly over the old program?  How do I keep track of these programs; do most people just 'fire and forget' and if no uninstall target is given do I have to manually delete everything? Unusual integral I got a clock as a gift recently. It has a very novel face in that the hour positions are given by a complex formula. For the most part, I have been able to verify the calculations presented as accurate, but the two o'clock identity has me stumped.  $$ \frac{\gamma}{\displaystyle{\int_0^\infty\frac{e^{-x^2}-e^{-x}}{x}\,dx}} $$  I know that $\gamma$ is the . And WolframAlpha tells me that $\int_0^\infty\frac{e^{-x^2}-e^{-x}}{x}\,dx=\frac{\gamma}{2}$ which  makes sense because  $$ \frac{\gamma}{\displaystyle{\int_0^\infty\frac{e^{-x^2}-e^{-x}}{x}\,dx}}=\frac{\gamma}{\displaystyle{\frac{\gamma}{2}}}=2 $$  It is not clear how I would show $\int_0^\infty\frac{e^{-x^2}-e^{-x}}{x}\,dx=\frac{\gamma}{2}$. Could anyone shed some light on this or point me to a source (book, article, etc...) where I can read up on this. The usual internet (listed above) resources have not been helpful to me. What does it mean if a Python object is "subscriptable" or not? Which types of objects fall into the domain of "subscriptable"? How do you debug PHP scripts? How do you debug PHP scripts?  I am aware of basic debugging such as using the Error Reporting. The breakpoint debugging in PHPEclipse is also quite useful.  What is the best (in terms of fast and easy) way to debug in phpStorm or any other IDE? How can I buy apps in the App Store without a credit card? While I'm waiting for my credit card to arrive, I still want to be able to buy some apps for my iPad!  Are there alternative ways to pay for apps, without resorting to someone else's credit card? I have this on the command line:    ln -sf $PWD/wine-   and then I hit Tab to complete the filename.  In earlier versions of Ubuntu, this worked just fine to complete the wine- filename (and as a side-effect $PWD would be expanded at that time).  But now it turns it in to  ln -sf \$PWD/wine-   which isn't what I meant at all and doesn't complete anything as the file does not literally start with $.  How do I get completion back to the less broken behaviour?  set tells me these are my current settings:  BASHOPTS=checkwinsize:cmdhist:expand_aliases:extquote:force_fignore:hostcomplete:interactive_comments:progcomp:promptvars:sourcepath SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor Suppose $G$ is a finite group and I know for every $k \leq |G|$ that exactly $n_k$ elements in $G$ have order $k$. Do I know what the group is? Is there a counterexample where two groups $G$ and $H$ have the same number of elements for each order, but $G$ is not isomorphic to $H$? I suspect that there is, but I haven't thought of one.