You simply need to start `mysql` and feed it with the content of `db.sql`:

    mysql -u user -p &lt; db.sql

If you want to run a script to a database:

    mysql -u user -p data_base_name_here &lt; db.sql

This is a much simpler example of what I&#39;m trying to do in my program but is a similar idea. In an, if statement how do I say not equal to?

Is `!=` correct?

    def test
      vara = 1
      varb = 2
      if vara == 1 &amp;&amp; varb != 3
        puts &quot;correct&quot;
      else
        puts &quot;false&quot;
      end
    end


How do you say not equal to in Ruby?

I have an array of subarrays in the following format:

    array
    (
        a =&gt; array ( id = 20, name = chimpanzee )
        b =&gt; array ( id = 40, name = meeting )
        c =&gt; array ( id = 20, name = dynasty )
        d =&gt; array ( id = 50, name = chocolate )
        e =&gt; array ( id = 10, name = bananas )
        f =&gt; array ( id = 50, name = fantasy )
        g =&gt; array ( id = 50, name = football )
    )

And I would like to group it into a new array based on the id field in each subarray.


    array
    (
        10 =&gt; array
              (
                e =&gt; array ( id = 10, name = bananas )
              )
        20 =&gt; array
              (
                a =&gt; array ( id = 20, name = chimpanzee )
                c =&gt; array ( id = 20, name = dynasty )
              )
        40 =&gt; array
              (
                b =&gt; array ( id = 40, name = meeting )
              )
        50 =&gt; array
              (
                d =&gt; array ( id = 50, name = chocolate )
                f =&gt; array ( id = 50, name = fantasy )
                g =&gt; array ( id = 50, name = football )
              )
    )

Group array by subarray values

Basically, I need to setup a database from a bash script. I have a script db.sql that does all this. Now how do I run this script from bash?

Database system is mysql

How to execute a .sql script from bash

<p>Basically, I need to setup a database from a bash script. I have a script db.sql that does all this. Now how do I run this script from bash?</p>
<p>Database system is mysql</p>


I previously created a MySQL table and now I want to find out what collation some of the fields are using. What SQL or MySQL commands can I use to discover this?



Discover collation of a MySQL column

I have a field of time Timestamp in my MySQL database which is mapped to a `DATE` datatype in my bean. Now I want a query by which I can fetch all records in the database for which the difference between the current timestamp and the one stored in the database is &gt; 20 minutes.

How can I do it?

**What i want is:**

    SELECT * FROM MyTab T WHERE T.runTime - now &gt; 20 minutes

Are there any MySQL functions for this, or any way to do this in SQL?


Calculating time difference between 2 dates in minutes

If I have a MySQL table looking something like this:

&lt;pre&gt;
company_name	action	pagecount
-------------------------------
Company A		PRINT	3
Company A		PRINT	2
Company A		PRINT	3
Company B		EMAIL	
Company B		PRINT	2
Company B		PRINT	2
Company B		PRINT	1
Company A		PRINT	3
&lt;/pre&gt;

Is it possible to run a MySQL query to get output like this:

&lt;pre&gt;
company_name	EMAIL	PRINT 1 pages	PRINT 2 pages	PRINT 3 pages
-------------------------------------------------------------
CompanyA		0		0				1				3
CompanyB		1		1				2				0
&lt;/pre&gt;

The idea is that `pagecount` can vary so the output column amount should reflect that, one column for each `action`/`pagecount` pair and then number of hits per `company_name`. I&#39;m not sure if this is called a pivot table but someone suggested that?


How can I return pivot table output in MySQL?

I have a query where I am using `GROUP_CONCAT` and a custom separator as my results may contain commas: &#39;----&#39;

This all works well, however it is still comma separated, so my output is:

    Result A----,Result B----,Result C----

How can I make it so the output is:

    Result A----Result B----Result C----

I thought this was the idea of a custom separator!

Failing that, can you escape commas in your results, so I can explode in PHP by the `GROUP_CONCAT` commas?

GROUP_CONCAT comma separator - MySQL

We are running a Java PoS (Point of Sale) application at various shops, with a MySql backend. I want to keep the databases in the shops synchronised with a database on a host server.

When some changes happen in a shop, they should get updated on the host server. How do I achieve this? 

Mysql database sync between two databases

I get this error when setting up a server in Django. It is sqlite3 which means it should create the .db file but it doesn&#39;t seem to be doing so. I&#39;ve stipulated SQLite as the backend and an absolute file path for where to put it, but no luck.

Is this a bug or am I doing something incorrect? (Was just thinking, is the absolute file path specified differently in Ubuntu?)

Here is the beginning of my settings.py file:


    # Django settings for OmniCloud project.

    DEBUG = True
    TEMPLATE_DEBUG = DEBUG

    ADMINS = (
    # (&#39;Your Name&#39;, &#39;your_email@example.com&#39;),
    )

    MANAGERS = ADMINS

    DATABASES = {
    &#39;default&#39;: {
        &#39;ENGINE&#39;: &#39;django.db.backends.sqlite3&#39;, # Add &#39;postgresql_psycopg2&#39;, &#39;postgresql&#39;, &#39;mysql&#39;, &#39;sqlite3&#39; or &#39;oracle&#39;.
        &#39;NAME&#39;: &#39;~/Harold-Server/OmniCloud.db&#39;,                      # Or path to database file if using sqlite3.
        &#39;USER&#39;: &#39;&#39;,                      # Not used with sqlite3.
        &#39;PASSWORD&#39;: &#39;&#39;,                  # Not used with sqlite3.
        &#39;HOST&#39;: &#39;&#39;,                      # Set to empty string for localhost. Not used with sqlite3.
        &#39;PORT&#39;: &#39;&#39;,                      # Set to empty string for default. Not used with sqlite3.
    }
    }


sqlite3.OperationalError: unable to open database file

You&#39;ll have to admit, to a newbie to rails and databases, the official explanation on rubyonrails.org makes all four of these tasks sound exactly the same. Quote:

    rake db:test:clone	Recreate the test database from
                        the current environment’s database schema

    rake db:test:clone_structure	Recreate the test database from the
                                    development structure

    rake db:test:load	Recreate the test database from the current schema.rb

    rake db:test:prepare	Check for pending migrations and load the test schema

I don&#39;t even know the difference between structure and schema. And what&#39;s  the difference between loading the current environment&#39;s schema and just loading schema.rb?

Just how similar (or different) are these tasks?

What&#39;s the difference between db:test:clone, db:test:clone_structure, db:test:load, and db:test:prepare?

Being a self-taught newbie, I created a large problem for myself. Before inserting data in to my database, I&#39;ve been converting apostrophes (&#39;) in a string, to double quotes (&quot;&quot;), instead of the required back-slash and apostrophe (\&#39;), which MySQL actually requires.

Before my table grows more than the 200,000 rows it already is, I thought it was best to rectify this issue immediately. So I did some research and found the SQL REPLACE function, which is great, but I&#39;m now confused.

In ASP, I was doing this:

    str = Replace(str,&quot;&#39;&quot;,&quot;&quot;&quot;&quot;)

If I look at my database in SQL Workbench, the symbol I converted is now a single quote (&quot;), which has confused me a little. I understand why it changed from double to single, but I don&#39;t know which one I&#39;m meant to be changing now. 

To go through and rectify my problem using SQL REPLACE, do I now convert single quotes (&quot;) to back-slash and apostrophes (\&#39;) or do I convert double quotes (&quot;&quot;) to back-slash and apostrophes (\&#39;)?

For example, this:

    SQL = &quot; SELECT REPLACE(myColumn,&quot;&quot;&quot;&quot;,&quot;\&#39;&quot;) FROM myTable &quot;

or this:

    SQL = &quot; SELECT REPLACE(myColumn,&quot;&quot;&quot;,&quot;\&#39;&quot;) FROM myTable &quot;

I hope I explained myself well, any suggestions gratefully received as always. Any queries about my question, please comment.

Many thanks

**-- UPDATE --**

I have tried the following queries but still fail to change the ( &quot; ) in the data:

    SELECT REPLACE(caption,&#39;\&quot;&#39;,&#39;\&#39;&#39;) FROM photos WHERE photoID = 3371
    SELECT REPLACE(caption,&#39;&quot;&#39;,&#39;\&#39;&#39;) FROM photos WHERE photoID = 3371
    SELECT REPLACE(caption,&#39;&quot;&quot;&#39;,&#39;\&#39;&#39;) FROM photos WHERE photoID = 3371

Yet if I search:

    SELECT COUNT(*) FROM photos WHERE caption LIKE &#39;%&quot;%&#39;

I get 16,150 rows.

**-- UPDATE 2 --**

Well, I have created a &#39;workaround&#39;. I managed to convert an entire column pretty quickly writing an ASP script, using this SQL:

    SELECT photoID, caption FROM photos WHERE caption LIKE &#39;%&quot;&quot;%&#39;;

and then in ASP I did:

    caption = Replace(caption,&quot;&quot;&quot;&quot;,&quot;\&#39;&quot;)

But I would still like to know why I couldn&#39;t achieve that with SQL?

MySQL - Replace Character in Columns

I want to get a list of column names from a table in a database. Using pragma I get a list of tuples with a lot of unneeded information. Is there a way to get only the column names? So I might end up with something like this:

&gt; [Column1, Column2, Column3, Column4]

The reason why I absolutely need this list is because I want to search for a column name in the list and get the index because the index is used in a lot of my code.

Is there a way of getting a list like this?

Thanks

Is there a way to get a list of column names in sqlite?

I work with Amazon Linux instances and I have a couple scripts to populate data and install all the programs I work with, but a couple of the programs ask:

    Do you want to continue [Y/n]?

and pause the install.  I want to auto answer &quot;Y&quot; in all cases, I&#39;m just now sure how to do it.












How do I script a &quot;yes&quot; response for installing programs?

I am trying to use addr2line command in Unix but everytime it is giving the same output as ??:0. I am giving command as `addr2line -e  a.out  0x4005BDC` . I got this address while running this a.out executable with `valgrind` tool to find the memory leakage. I also compiled the source code with `-g` option. 

How to use the addr2line command in Linux?

How do I get the [Olson timezone name][1] (such as `Australia/Sydney`) corresponding to the value given by C&#39;s [`localtime`][2] call?

This is the value overridden via `TZ`, by symlinking `/etc/localtime`, or setting a `TIMEZONE` variable in time-related system configuration files.

  [1]: http://en.wikipedia.org/wiki/Tz_database#Names_of_time_zones
  [2]: http://docs.python.org/py3k/library/time.html#time.localtime

Get the Olson TZ name for the local timezone?

I wrote simple C programs, which are using sockets (&#39;client&#39; and &#39;server&#39;). 
(UNIX/Linux usage)

The server side simply creates a socket:

    sockfd = socket(AF_INET, SOCK_STREAM, 0);

And then binds it to sockaddr:

    bind(sockfd, (struct sockaddr *) &amp;serv_addr, sizeof(serv_addr));

And listens (and accepts and reads):

    listen(sockfd,5);
    newsockfd = accept(sockfd, (struct sockaddr *) &amp;cli_addr, &amp;clilen);
    read(newsockfd,buffer,255);

The client creates the socket, and then writes to it.

Now, I want to convert this simple connection into an SSL connection, in the plainest, most idyllic, neatest and quickest way.  

I&#39;ve tried to add [OpenSSL][1] to my project, but I can&#39;t find an easy way to implement what I want.

  [1]: http://en.wikipedia.org/wiki/OpenSSL


Turn a simple socket into an SSL socket

How can I use `sips`, `imagemagic`, or another tool to convert an image to black and white (grayscale) via the command line? 

How can I convert an image to grayscale via the command line?

I&#39;m dynamically generating `config.mk` with a bash script which will be used by a Makefile. The file is constructed with:

    cat &gt; config.mk &lt;&lt;CFG
    SOMEVAR := $value_from_bash1
    ANOTHER := $value_from_bash2
    CFG
How do I ensure that the generated file really contains the contents of `$value_from_bash*`, and not something expanded / interpreted? I probably need to escape `$` to `$$` and `\` to `\\`, but are there other characters that needs to be escaped? Perhaps there is a special literal assignment I&#39;ve not heard of?

Spaces seems to be troublesome too:

    $ ls -1
    a b
    a
    $ cat Makefile
    f := a b
    default_target:
        echo &quot;$(firstword $(wildcard ${f}))&quot;
    $ make
    a
If I use `f := a\ b` it works (using quotes like `f := &#39;a b&#39;` did not work either, makefile just treats it as a regular character)

How do I properly escape data for a Makefile?

When I try to use the `read` command in Bash like this:

    echo hello | read str
    echo $str

Nothing echoed, while I think `str` should contain the string `hello`. Can anybody please help me understand this behavior?

How to use the read command in Bash?

I am trying to change the values in a text file using sed in a Bash script with the line,

    sed &#39;s/draw($prev_number;n_)/draw($number;n_)/g&#39; file.txt &gt; tmp

This will be in a `for` loop. Why is it not working?






sed substitution with Bash variables

To run a process in the background in bash is fairly easy.

    $ echo &quot;Hello I&#39;m a background task&quot; &amp;
    [1] 2076
    Hello I&#39;m a background task
    [1]+  Done                    echo &quot;Hello I&#39;m a background task&quot;

However the output is verbose. On the first line is printed the job id and process id of the background task, then we have the output of the command, finally we have the job id, its status and the command which triggered the job.

Is there a way to suppress the output of running a background task such that the output looks exactly as it would without the ampersand at the end? I.e:

    $ echo &quot;Hello I&#39;m a background task&quot; &amp;
    Hello I&#39;m a background task

The reason I ask is that I want to run a background process as part of a tab-completion command so the output of that command must be uninterrupted to make any sense.


Content Type	Original Author	Original Content on Stackoverflow
Question	user623879	View Question on Stackoverflow
Solution 1 - Mysql	aioobe	View Answer on Stackoverflow
Solution 2 - Mysql	Celso Dantas	View Answer on Stackoverflow

How to execute a .sql script from bash

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

Group array by subarray values

How do you say not equal to in Ruby?

Attributions