Hello Im getting the following error when trying to update my database:      Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42S22]: Column not found: 1054 Unknown column ''1'' in 'where clause''   Im getting three variables via POST They are:   a) the Column I want to change   b) The new value for the column  c) the ID which row to change...  Im using PDO, this is my Query with param-binding and execution:  $stmt = $db-&gt;prepare('UPDATE `artists` SET `:spalte` = `:wert` WHERE  `id` = `:pk` '); $stmt-&gt;bindParam(':spalte', $name); $stmt-&gt;bindParam(':wert', $value); $stmt-&gt;bindParam(':pk', $pk); $stmt-&gt;execute();   I hope someone will understand this error...  Best Regards  Dave
Why can't I pass the table name to a prepared PDO statement?  $stmt = $dbh-&gt;prepare('SELECT * FROM :table WHERE 1'); if ($stmt-&gt;execute(array(':table' =&gt; 'users'))) {     var_dump($stmt-&gt;fetchAll()); }   Is there another safe way to insert a table name into a SQL query? With safe, I mean that I don't want to do  $sql = "SELECT * FROM $table WHERE 1"
Why cant we replace diode connected BJTs by simple diodes in a current mirror circuit? I've found a couple of references () that suggest using final as much as possible and I'm wondering how important that is. This is mainly in the the context of method parameters and local variables, not final methods or classes. For constants, it makes obvious sense.  On one hand, the compiler can make some optimizations and it makes the programmer's intent clearer. On the other hand, it adds verbosity and the optimizations may be trivial.  Is it something I should make an effort to remember? My router can do port-forwarding based on MAC addresses. That is, a specific MAC will get a specific IP, for which I can configure a set of ports to be forwarded. In order to easily change that set of ports, I'd like to have different connections in the Network manager.  How do I change the MAC address for a network connection? I know that an easy to handle formula for the CDF of a normal distribution is somewhat missing, due to the complicated error function in it.  However, I wonder if there is a a nice formula for $N(c_{-} \leq x &lt; c_{+}| \mu, \sigma^2)$. Or what the "state of the art" approximation for this problem might be. (Posted here as probably applies to all sites).  I was examining my reputation gain yesterday on Stack Overflow: 190. I believe I should have hit the 200 cap. Mainly due to         Respectively, I had 10, 7, 3, and 2 upvotes on those questions alone. There are a couple of other minnows in the list but the above alone should enable me to hit the cap.  There was a user removed sometime yesterday which knocked off 10 points (and possibly accounts for the disparity) but I think (1) the cap should have been recalibrated and (2) I answered (3) after this event before turning in for the night.  I checked all the usual suspects: the reputation graph on your profile and  the achievements tab, but they are all showing 190. Why am I not burned by a strong wind? Black holes and positive/negative-energy particles I was reading Brian Greene's "Hidden Reality" and came to the part about Hawking Radiation. Quantum jitters that occur near the event horizon of a black hole, which create both positive-energy particles and negative-energy particles, produce the so-called Hawking radiation. However, I do not understand why only the negative-energy particles are being absorbed into the black hole, while the positive-energy particles shoot outward. Shouldn't there be 50/50 chance that each type of particle is being absorbed by the black hole? Also, the book mentions that a negative-energy particle would appear to an observer inside the black hole as positive. Why? New "[tag:" syntax interferes with Markdown links Why is Excel truncating my 16-digit numbers? If I type in a 16 digit number (format: number, no decimals) it changes the number on me. Example: 1234567812345678 changes the view to 1234567812345670.    If I type it in as a general format it changes the numbers above so it displays 1.23457E+15 but if you click on the cell, the display shows the last digit as a 0 instead of an 8 once again.   I opened the file on a different computer and same issue now with it.  I have changed the auto correction and auto formatting all to no avail.  Help! I am getting error:     The argument 2 of the "JSON_VALUE or JSON_QUERY" must be a string literal   ...while trying to pass variable as parameter to JSON_QUERY function. Please help me to resolve it.  DECLARE @cnt INT = 1; DECLARE @cnt_total INT = 1; DECLARE @json NVARCHAR(MAX); DECLARE @json1 NVARCHAR(MAX); declare @str  VARCHAR(200);  WHILE @cnt &lt;= 10 BEGIN     set @str = '$.Seasons[0].Products['+convert(varchar,@cnt)+'].ProductChannels';     set @str = char(39) +@str+ char(39);     PRINT @STR     select @json = json_query(jfile,@STR) from Import.tstjson; --MORE CODE         SET @cnt = @cnt + 1; END   Sample data:  {   "Seasons": [     {       "Season": "12321231",       "Products": [         {           "ProductId": "211",           "ProductChannels": [             {               "ChannelId": 1,               "WeekQuantities": []             }           ],           "ccc": 3,           "Tttt": 4         }       ]     }   ] } Whenever light rays are entering a denser medium they bend towards the normal.  Why do rays choose the path towards the normal? Why cannot they choose the path away form the normal? So, I'm working on a control station that has buttons. It is a one-mesh creation, that means, I don't want to create buttons and things like that separated from the main mesh, but as you can see, I have problems. I would like to make the highlighted parts to be one with the main part around them. I've tried everything, and I have this problem on multiple creations. Any idea?  Update: I've added another example of the problem. I want them to be one face, instead of two. (2nd picture) Get image pixels of prescribed color subideals of an ideal If $R$ is a ring, J is an ideal in $R$, and $I$ is an ideal of $J$ (with $J$ considered as a ring), does it follow that $I$ is an ideal of $R$?  That is, is $I$ necessarily closed under multiplication by elements of $R$?  Surely $I$ is closed under multiplication by elements of $J$ (since $I$ is an ideal of $J$).  The "obvious" approach to proof fails so quickly that it must be false, that "an ideal of an ideal is not necessarily an ideal of the big ring".  Please provide a counterexample.  (Or a proof?) Why is the field inside a conducting shell zero when only external charges are present? I have a question related to modeling short time-series. It is not a question , but how. What method would you recommend for modeling (very) short time-series (say of length $T \leq 20$)? By "best" I mean here the most robust one, that is the least prone to errors due the fact of limited numbers of observations. With short series single observations could influence the forecast, so the method should provide a cautious estimate of errors and possible variability connected to the forecast. I am generally interested in univariate time-series but it would be also interesting to know about other methods. Prove that the difference between two rational numbers is rational This is a terribly simple question I'm sure, but I can't find a work-around in my proof. I must prove that the difference between two rational numbers is thus rational. Here is my attempt:     Let $a$ and $b$ be rational numbers. Therefore, \begin{align}  a=\frac{\lambda}{\beta},\:b=\frac{\xi}{\zeta},\:\ni\:\lambda,\beta,\xi,\zeta\in\mathbb{Z},\tag{1} \end{align} which gives us \begin{align}  a-b=\frac{\lambda}{\beta}-\frac{\xi}{\zeta}=\frac{\lambda\zeta-\xi\beta}{\beta\xi}.\tag{2} \end{align}   So I have shown that $a$ and $b$ are rational numbers which, by definition, can be represented by the quotient of two integers. But now how do I tackle the problem of the difference? By definition the difference between two integers is an integer. Does that require that this difference is thus rational?  Thank you for your time, How to change boot priority? "It looks straightforward, but actually it isn't" In , I asked about proof of statements which are simple but incorrect.   Here, I ask about statements which seems, at a first glance, straightforward, but if we try to write a proof, we can see it's much harder than it looked. So I expect the answers to contain:   the statement; why it looks easy to prove; why actually it isn't. Where is the itoa function in Linux?