the type is integer like :

    int(11) 

is good  for indexing and conditions like `&gt; &lt; =`

You want to use the [TIMESTAMP data type][1].  
It&#39;s stored as an epoch value, but MySQL displays the value as &#39;YYYY-MM-DD HH:MM:SS&#39;.


  [1]: http://dev.mysql.com/doc/refman/5.5/en/datetime.html

&gt;**MySql DateTime** data type store the date in format &#39;YYYY-MM-DD HH:MM:SS&#39; with range from &#39;1000-01-01 00:00:00&#39; to &#39;9999-12-31 23:59:59&#39;.
&gt;
&gt;**MySql TIMESTAMP** data type store the date in format &#39;YYYY-MM-DD HH:MM:SS&#39; with range from &#39;1970-01-01 00:00:01&#39; UTC to &#39;2038-01-19 03:14:07&#39; UTC.


**Unix TIMESTAMP** is the number of seconds since `1970-01-01`, if you want to store the unix Timestamp in `mysql` db you should use `int(11)` with attribute `UNSIGNED` (to permit only positive numbers), and if you want to save the number of microseconds you should use `bigint(20)`,..

If you want to get the `unixtimestamp` in readable format in your select query 
You can use

`SELECT FROM_UNIXTIME(CAST(yourtable.start_time as UNSIGNED)) as date_time`

  
If you are using `php` you can use:  

    $unixtimestamp= time();//1544619186

    echo(date(&quot;Y-m-d&quot;, $unixtimestamp));//2018-12-12

If you want to display the datetime using the **local timezone** in **Javascript** use this function

  

      function timeConverter(UNIX_timestamp){
            var date = new Date(UNIX_timestamp*1000);
            var year = date.getFullYear();
            var month = (&quot;0&quot;+(date.getMonth()+1)).substr(-2);
            var day = (&quot;0&quot;+date.getDate()).substr(-2);
            var hour = (&quot;0&quot;+date.getHours()).substr(-2);
            var minutes = (&quot;0&quot;+date.getMinutes()).substr(-2);
            var seconds = (&quot;0&quot;+date.getSeconds()).substr(-2);
        
            return year+&quot;-&quot;+month+&quot;-&quot;+day+&quot; &quot;+hour+&quot;:&quot;+minutes+&quot;:&quot;+seconds;
        }
       console.log(timeConverter(value));// 2018-14-12 13:11:33

(In this case the server should return the unixTimestamp as it is:
`SELECT yourtable.start_time as date_time`)

BIGINT UNSIGNED NOT NULL

Epoch representation in seconds can fit into `INT(11)`
If the timestamp has milliseconds, `INT(20)` can be used.

I know that global variables are bad.

But if I am using node&#39;s module &quot;util&quot; in 40 files in my framework, isn&#39;t it better to just declare it as a global variable like:

    util = require(&#39;util&#39;);

in the index.js file instead of writing that line in 40 files?

Cause I often use the same 5-10 modules in each file, that would save a lot of time instead of copy paste all the time.

Isn&#39;t DRY good in this case?

Global variables for node.js standard modules?

Currently when I&#39;m using GIT I create a branch for each job and make various commits before I&#39;m finished. I then merge back with my master branch and push upstream. I&#39;m likely to have several branches at any one time and also flick between them mid-job as things crop up.

But most of these commits are just save points, i.e. not that important in the grand scheme of things. So when I merge the branch, I&#39;d like it if the branch logs didn&#39;t merge with the master logs. 

Is there a way to just merge the log message for commit g below (and not commits c or e)? 



    a [master] 
    |
    b (create branch &#39;job&#39;)
    |\
    | \
    |  c 
    |  |
    d  e
    |  |
    f  g (next step is to merge &#39;job&#39; branch with &#39;master&#39;)

Merge GIT branch without commit log

What data type should I use for saving **`unix_timestamp`** value (MySQL)?

What is the data type for unix_timestamp (MySQL)?

<p>What data type should I use for saving <strong><code>unix_timestamp</code></strong> value (MySQL)?</p>


I have a table `A` and a table `B`.  `A` has a foreign key to `B` on `B`&#39;s primary key, `B_ID`.

For some reason (I know there are legitimate reasons) it is not using an index when I join these two tables on the key.

Do I need to separately create an index on `A.B_ID` or should the existence of a foreign key provide that?

Do I need to create indexes on foreign keys on Oracle?

I&#39;m doing some basic sql on a few tables I have, using a union(rightly or wrongly)

but I need remove the duplicates. Any ideas?

    select * from calls
    left join users a on calls.assigned_to= a.user_id
    where a.dept = 4 
    union
    select * from calls
    left join users r on calls.requestor_id= r.user_id
    where r.dept = 4

remove duplicates from sql union

Here is what I want to do:  
  
current table:  

    +----+-------------+  
    | id | data        |  
    +----+-------------+  
    |  1 | max         |  
    |  2 | linda       |  
    |  3 | sam         |  
    |  4 | henry       |  
    +----+-------------+  


Mystery Query ( something like `&quot;UPDATE table SET data = CONCAT(data, &#39;a&#39;)&quot;` )

resulting table:  

    +----+-------------+  
    | id | data        |  
    +----+-------------+  
    |  1 | maxa        |  
    |  2 | lindaa      |  
    |  3 | sama        |  
    |  4 | henrya      |  
    +----+-------------+  

thats it! I just need to do it in a single query, but can&#39;t seem to find a way. I am using mySQL on bluehost (I think its version 4.1)

Thanks everyone.


SQL UPDATE all values in a field with appended string CONCAT not working

I want get the value from `Exec(@sql)` and assign to `@Rowcount(int)`

Here is my query:


    &#39;SET @RowCount = (select count(*) 
                        FROM dbo.Comm_Services 
                       WHERE CompanyId = &#39;+cast(@CompanyId as char)+&#39; and &#39;+@condition+&#39;)&#39;



Return value from exec(@sql)

Given a table with a datetime column, how do I query for rows where the date matches the value I specify but ignores the time portion?

For example, `select * from sales where salesDate = &#39;11/11/2010&#39;`

For this query we don&#39;t care about the time. Other queries require the time component so we can&#39;t store only the date component.

Thanks!


How to select rows for a specific date, ignoring time in SQL Server

I have 2 tables in my database.  One is for orders, and one is for companies.

Orders has this structure:

    OrderID     |     attachedCompanyIDs
    ------------------------------------
       1                     1,2,3
       2                     2,4

And Company has this structure:

    CompanyID      |        name
    --------------------------------------
        1                 Company 1
        2                 Another Company
        3                 StackOverflow
        4                 Nothing

To get an order&#39;s companies names, I can do a query as such:

    SELECT name FROM orders,company
    WHERE orderID = 1 AND FIND_IN_SET(companyID, attachedCompanyIDs)

That query works fine, but the following query does not.

    SELECT name FROM orders,company
    WHERE orderID = 1 AND companyID IN (attachedCompanyIDs)

Why does the first query work but not the second one?

The first query returns:

    name
    ---------------
    Company 1
    Another Company
    StackOverflow

The second query only returns:

    name
    ---------------
    Company 1

Why is this, why does the first query return all the companies, but the second query only returns the first one?


FIND_IN_SET() vs IN()

Let me start right off the bat by saying that I know this is not the best solution. I know it&#39;s kludgy and a hack of a feature. *But that&#39;s why I&#39;m here!*

This question/work builds off [some discussion on Quora with Andrew Bosworth][1], creator of Facebook&#39;s news feed.

**I&#39;m building a news feed** of sorts. It&#39;s built solely in `PHP` and `MySQL`.

![alt text][2]

----------


## The MySQL ##

The relational model for the feed is composed of two tables. One table functions as an activity log; in fact, it&#39;s named `activity_log`. The other table is `newsfeed`. *These tables are nearly identical.*

The **schema for the log** is `activity_log(uid INT(11), activity ENUM, activity_id INT(11), title TEXT, date TIMESTAMP)`

...and the **schema for the feed** is `newsfeed(uid INT(11), poster_uid INT(11), activity ENUM, activity_id INT(11), title TEXT, date TIMESTAMP)`.

**Any time a user does something** relevant to the news feed, for example asking a question, **it will get logged to the activity log** immediately.

----------

## Generating the news feeds ##

Then **every X minutes** (5 minutes at the moment, will change to 15-30 minutes later), **I run a cron job** that executes the script below. This script loops through all of the users in the database, finds all the activities for all of that user&#39;s friends, and then writes those activities to the news feed.

At the moment, the `SQL` that culls the activity (called in `ActivityLog::getUsersActivity()`) has a `LIMIT 100` imposed for performance* reasons. *Not that I know what I&#39;m talking about.

    &lt;?php
    
    $user = new User();
    $activityLog = new ActivityLog();
    $friend = new Friend();
    $newsFeed = new NewsFeed();
    
    // Get all the users
    $usersArray = $user-&gt;getAllUsers();
    foreach($usersArray as $userArray) {
      
      $uid = $userArray[&#39;uid&#39;];
      
      // Get the user&#39;s friends
      $friendsJSON = $friend-&gt;getFriends($uid);
      $friendsArray = json_decode($friendsJSON, true);
      
      // Get the activity of each friend
      foreach($friendsArray as $friendArray) {
        $array = $activityLog-&gt;getUsersActivity($friendArray[&#39;fid2&#39;]);
        
        // Only write if the user has activity
        if(!empty($array)) {
          
          // Add each piece of activity to the news feed
          foreach($array as $news) {
            $newsFeed-&gt;addNews($uid, $friendArray[&#39;fid2&#39;], $news[&#39;activity&#39;], $news[&#39;activity_id&#39;], $news[&#39;title&#39;], $news[&#39;time&#39;]);
          }
        }
      }
    }


----------

## Displaying the news feeds ##

In the client code, when fetching the user&#39;s news feed, I do something like:

    $feedArray = $newsFeed-&gt;getUsersFeedWithLimitAndOffset($uid, 25, 0);

    foreach($feedArray as $feedItem) {

    // Use a switch to determine the activity type here, and display based on type
    // e.g. User Name asked A Question
    // where &quot;A Question&quot; == $feedItem[&#39;title&#39;];

    }


----------

## Improving the news feed ##

Now forgive my limited understanding of the best practices for developing a news feed, but I understand the approach I&#39;m using to be a limited version of what&#39;s called **fan-out on write**, limited in the sense that I&#39;m running a cron job as an intermediate step instead of writing to the users&#39; news feeds directly. But this is very different from a pull model, in the sense that the user&#39;s news feed is not compiled on load, but rather on a regular basis.

This is a large question that probably deserves a large amount of back and forth, but I think it can serve as a touchstone for many important conversations that new developers like myself need to have. I&#39;m just trying to figure out what I&#39;m doing wrong, how I can improve, or how I should maybe even start from scratch and try a different approach.

One other thing that bugs me about this model is that it works based on recency rather than relevancy. If anyone can suggest how this can be improved to work relevancy in, I would be all ears. I&#39;m using Directed Edge&#39;s API for generating recommendations, but it seems that for something like a news feed, recommenders won&#39;t work (since nothing&#39;s been favorited previously!).


  [1]: http://www.quora.com/What-are-best-practices-for-building-something-like-a-News-Feed
  [2]: http://i.stack.imgur.com/KPvit.gif

How can I improve this PHP/MySQL news feed?

I&#39;d like to get all of a mysql table&#39;s col names into an array in php?

Is there a query for this? 

MySQL query to get column names?

I have this MySQL query.

I have database fields with this contents

    sports,shopping,pool,pc,games 
    shopping,pool,pc,games 
    sports,pub,swimming, pool, pc, games   

Why does this like query does not work?
I need the fields with either sports or pub or both?

    SELECT * FROM table WHERE interests LIKE (&#39;%sports%&#39;, &#39;%pub%&#39;)


MySQL Like multiple values

Say I have an `System.String[]` type object. I can query the type object to determine if it is an array 

    Type t1 = typeof(System.String[]);
    bool isAnArray = t1.IsArray; // should be true

However how do I get a type  object of the array item from t1

    Type t2 = ....; // should be typeof(System.String)

How do I get the Array Item Type from Array Type in .net

In Java the numeric types all descend from Number so I would use

    (x instanceof Number).

What is the python equivalent?

How can I check if my python object is a number?

let&#39;s say I have a column on my table defined the following:

    &quot;MyColumn&quot; smallint NULL

Storing a value like 0, 1 or something else should need 2 bytes (1). But how much space is needed if I set &quot;MyColumn&quot; to NULL? Will it need 0 bytes?

Are there some additional needed bytes for administration purpose or such things for every column/row?


(1) http://www.postgresql.org/docs/9.0/interactive/datatype-numeric.html



How much disk-space is needed to store a NULL value using postgresql DB?

I&#39;m using lots of different records in a program, with some of them using the same field names, e.g.

    data Customer = Customer { ..., foo :: Int, ... }
    data Product = Product { ..., foo :: Int, ... }

Now as the accessor function &quot;foo&quot; is defined twice, I get the &quot;Multiple declarations&quot; error. One way to avoid this would be using different modules that are imported fully qualified, or simply renaming the fields (which I don&#39;t want to do).

What is the officially suggested way of dealing with this in Haskell?

Avoiding namespace pollution in Haskell

I&#39;d like to restrict the type of file that can be chosen from the native OS file chooser when the user clicks the Browse button in the `&lt;input type=&quot;file&quot;&gt;` element in HTML. I have a feeling it&#39;s impossible, but I&#39;d like to know if there _is_ a solution. I&#39;d like to keep solely to HTML and JavaScript; no Flash please.

Content Type	Original Author	Original Content on Stackoverflow
Question	jjz	View Question on Stackoverflow
Solution 1 - Sql	Haim Evgi	View Answer on Stackoverflow
Solution 2 - Sql	OMG Ponies	View Answer on Stackoverflow
Solution 3 - Sql	Ahmad Zahabi	View Answer on Stackoverflow
Solution 4 - Sql	Ramesh Krishnan	View Answer on Stackoverflow

What is the data type for unix_timestamp (MySQL)?

Sql Problem Overview

Sql Solutions

Solution 1 - Sql

Solution 2 - Sql

Solution 3 - Sql

Solution 4 - Sql

Merge GIT branch without commit log

Global variables for node.js standard modules?

Attributions