    select * from *table_name* where *datetime_column* between &#39;01/01/2009&#39; and curdate()

or using `&gt;=` and `&lt;=` :

    select * from *table_name* where *datetime_column* &gt;= &#39;01/01/2009&#39; and *datetime_column* &lt;= curdate()

All the above works, and here is another way if you just want to number of days/time back rather a entering date

    select * from *table_name* where *datetime_column* BETWEEN DATE_SUB(NOW(), INTERVAL 30 DAY)  AND NOW() 

You can use `now()` like:

    Select data from tablename where datetime &gt;= &quot;01-01-2009 00:00:00&quot; and datetime &lt;= now();



Late answer, but the accepted answer didn&#39;t work for me.   
If you set both start and end dates manually (not using `curdate()`), make sure to **specify the hours, minutes and seconds** (`2019-12-02 23:59:59`) on the end date or you won&#39;t get any results from that day, i.e.:

This **WILL include** records from `2019-12-02`:

    SELECT *SOMEFIELDS* FROM *YOURTABLE* where *YOURDATEFIELD* between &#39;2019-12-01&#39; and &#39;2019-12-02 23:59:59&#39;

This **WON&#39;T include** records from `2019-12-02`:


    SELECT *SOMEFIELDS* FROM *YOURTABLE* where *YOURDATEFIELD* between &#39;2019-12-01&#39; and &#39;2019-12-02&#39;

Whenever I consider algorithms/data structures I tend to replace the log(N) parts by constants. Oh, I know log(N) diverges - but does it matter in real world applications?

&gt; log(infinity) &lt; 100  for all practical purposes.

I am really curious for real world examples where this doesn&#39;t hold.

To clarify:

 * I understand O(f(N))
 * I am curious about real world examples where the **asymptotic** behaviour matters more than the **constants** of the actual performance.
 * If log(N) can be replaced by a constant it still can be replaced by a constant in O( N log N).

This question is for the sake of (a) entertainment and (b) to gather arguments to use if I run (again) into a controversy about the performance of a design.

O(log N) == O(1) - Why not?

In particular 

 1. Create a function to take an array and an index as parameters.
 2. Create a n element array.
 3. Create a n count loop.
 4. Inside the loop on a new thread assign a new instance of the object to the array using the indexer passed in. 

I know how to manage the threads etc. I am interested in know if this is thread safe way of doing something.
 

     class Program
    {
        // bogus object
        class SomeObject
        {
            private int value1;
            private int value2;

            public SomeObject(int value1, int value2)
            {
                this.value1 = value1;
                this.value2 = value2;
            }
        }
       
        static void Main(string[] args)
        {

            var s = new SomeObject[10];
            var threads = Environment.ProcessorCount - 1;
            var stp = new SmartThreadPool(1000, threads, threads);
            for (var i = 0; i &lt; 10; i++)
            {
                stp.QueueWorkItem(CreateElement, s, i);
            }

        }

        static void CreateElement(SomeObject[] s, int index)
        {
            s[index] = new SomeObject(index, 2);
        }
    }

Are C# arrays thread safe?

How to select data from mysql table past date to current date? For example, Select data from 1 january 2009 until current date ??

My column &quot;datetime&quot; is in datetime date type. Please help, thanks


Edit:

If let say i want to get day per day data from 1 january 2009, how to write the query? Use count and between function? 

Select mysql query between date?

How to select data from mysql table past date to current date? For example, Select data from 1 january 2009 until current date ??
My column "datetime" is in datetime date type. Please help, thanks
Edit:
If let say i want to get day per day data from 1 january 2009, how to write the query? Use count and between function?

I&#39;m trying to select all rows that contain only alphanumeric characters in MySQL using:

    SELECT * FROM table WHERE column REGEXP &#39;[A-Za-z0-9]&#39;;

However, it&#39;s returning all rows, regardless of the fact that they contain non-alphanumeric characters.


SELECT only rows that contain only alphanumeric characters in MySQL

I&#39;m setting up a table that might have upwards of 70 columns. I&#39;m now thinking about splitting it up as some of the data in the columns won&#39;t be needed every time the table is accessed. Then again, if I do this I&#39;m left with having to use joins. 

At what point, if any, is it considered too many columns? 

mysql - how many columns is too many?

Maybe it&#39;s an obvious question, but I want to be sure.

How can i know if it MySQLnd is the active driver?

I&#39;m runing PHP 5.3 and MySQL 5.1.37.
In phpinfo() mysqlnd is listed but only with this I can&#39;t be sure if I&#39;m using MySQLnd or the old driver...

Extract of phpinfo() output

    mysql
    MySQL Support	enabled
    Active Persistent Links 	0
    Active Links 	0
    Client API version 	mysqlnd 5.0.5-dev - 081106 - $Revision: 1.3.2.27 $ 
    
    mysqli
    MysqlI Support	enabled
    Client API library version 	mysqlnd 5.0.5-dev - 081106 - $Revision: 1.3.2.27 $
    Active Persistent Links 	0
    Inactive Persistent Links 	0
    Active Links 	26 
    
    mysqlnd
    mysqlnd	enabled
    Version 	mysqlnd 5.0.5-dev - 081106 - $Revision: 1.3.2.27 $ 
    
    PDO
    PDO support	enabled
    PDO drivers 	mysql
    
    pdo_mysql
    PDO Driver for MySQL	enabled
    Client API version 	mysqlnd 5.0.5-dev - 081106 - $Revision: 1.3.2.27 $ 

I&#39;m using PDO, and PDO driver says mysql...




How to know if MySQLnd is the active driver?

We offer a platform for video- and audio-clips, photos and vector-grafics. We started with MySQL as the database backend and recently included [MongoDB][1] for storing all meta-information of the files, because MongoDB better fits the requirements. For example: photos may have [Exif][2] information, videos may have audio-tracks where we to want to store the meta-information of, too. Videos and vector-graphics don&#39;t share any common meta-information, etc. so I know, that MongoDB is perfect to store this unstructured data and keep it searchable.

However, we continue developing our platform and adding features. Now one of the next steps will be providing a forum for our users. The question that now arises is: use the MySQL database, which would be a good choice for storing forums and forum-posts, etc. or use MongoDB for this, too?

So the question is: when to use MongoDB and when to use a RDBMS. What would you take, mongoDB or MySQL, if you had the choice and why would you take it?

  [1]: http://www.mongodb.org/display/DOCS/Home
  [2]: http://en.wikipedia.org/wiki/Exchangeable_image_file_format


When to use MongoDB or other document oriented database systems?

Currently every time I add an entry to my database, the auto increment value increments by 1, as it should. However, it is only at a count of 47. So, if I add a new entry, it will be 48, and then another it will be 49 etc.

I want to change what the current Auto Increment counter is at. I.e. I want to change it from 47 to say, 10000, so that the next value entered, will be 10001. How do I do that?


Changing the current count of an Auto Increment value in MySQL?

I&#39;m making a web app to manage product SKUS. One part of that is to associate SKUs with product names. On each row of a table, I list a SKU and display a `&lt;select&gt;` box with product names. The product that&#39;s currently associated with that SKU in the database is given an attribute like `selected=&quot;selected&quot;`. This can be changed and updated via AJAX.

There are a **lot** of product `&lt;option&gt;`s - 103 to be exact - and this list is repeated in the `&lt;select&gt;` on each row.

From another input on the page, I am using jQuery AJAX requests to add new SKU/product associations, and to make it clear that they&#39;re added instantly, I insert them into the **top** of the table with a little highlight effect. As the number of SKUs increases past 10 or so, if I refresh the page (which loads everything back out of the database ordered by product name), Firefox starts to show some wrong options as selected by default. It is not consistent about which incorrect option it shows, but it seems to be mixing up the options that existed before the page reload.

If I inspect the `&lt;select&gt;` using Firebug, the `select=&quot;selected&quot;` is on the correct `&lt;option&gt;` tag. Refreshing the page (or leaving and typing this page&#39;s URL back in to return) does not make it show up correctly, but **hard refreshing (Ctrl+F5) does**.

Both Chrome and IE7 display this correctly in the first place.

My theory is that this is a result of a faulty cache strategy by Firefox. Does that sound right? Is there any way I can say in my code &quot;if this page is refreshed, make it a hard refresh - reload everything from scratch?&quot;

## Update

To solve this problem, I changed strategies.

   - Previously, I put a `&lt;select&gt;` with a long list of `&lt;option&gt;`s on each table row, with the current value set as default
   - Now, I put the current value in a `&lt;span&gt;`. If the user clicks a &quot;change&quot; button, I replace the `&lt;span&gt;` with a `&lt;select&gt;`, and the &quot;change&quot; button becomes a &quot;confirm&quot; button. If they change options and click confirm, AJAX updates the database, the and the `&lt;select&gt;` goes back to being a `&lt;span&gt;`, this time with the new value.

This has two benefits:

  - It fixes the bug described above
  - It requires **far** fewer DOM elements on the page (all those redundant `&lt;option&gt;`s)

Why doesn&#39;t Firefox show the correct default select option?

I&#39;m currently using jQuery to return some JSON results.  Once these results are returned, I&#39;m using them to pre-populate fields in my form.

However, I need some help in pre-selecting items in a drop down box.  For example, I have a select box (this is shortened):

    &lt;select id=&quot;startTime&quot;&gt;
    &lt;option value=&quot;14:00:00&quot;&gt;2:00 pm&lt;/option&gt;
    &lt;option value=&quot;15:00:00&quot;&gt;3:00 pm&lt;/option&gt;
    &lt;option value=&quot;16:00:00&quot;&gt;4:00 pm&lt;/option&gt;
    &lt;option value=&quot;17:00:00&quot;&gt;5:00 pm&lt;/option&gt;
    &lt;option value=&quot;18:00:00&quot;&gt;6:00 pm&lt;/option&gt;
    &lt;/select&gt;

And if my JSON value is:

     var start_time = data[0].start  // Let&#39;s say this is &#39;17:00:00&#39;

How can I, using jQuery, make the option with value &#39;17:00:00&#39; selected?

     &lt;option value=&quot;17:00:00&quot; selected=&quot;selected&quot;&gt;5:00 pm&lt;/option&gt;

jQuery / Programmatically Select an Option in Select Box

How to write SQL so that the result can be ordered first by column A then by column B. Something like below: 

```sql
SELECT * FROM tbl WHERE predictor ORDER by col_A and ORDER by col_B
```

How to order by column A and then by column B?

    &lt;select size=&quot;2&quot;&gt;
    &lt;option selected=&quot;selected&quot;&gt;Input your option&lt;/option&gt;
    &lt;option&gt;Input your option&lt;/option&gt;
    &lt;/select&gt;


What is the best way, using jQuery, to elegantly unselect the &lt;select&gt; option?

Best way to unselect a &lt;select&gt; in jQuery?

    SELECT * FROM table ORDER BY string_length(column);

Is there a MySQL function to do this (of course instead of `string_length`)?



MySQL - How to select data by string length

I&#39;m sure there&#39;s a good simple elegant one-liner in Ruby to give you the number of days in a given month, accounting for year, such as &quot;February 1997&quot;.  What is it?

How to get the number of days in a given month in Ruby, accounting for year?

What is the cleanest and most Pythonic way to get tomorrow&#39;s date? There must be a better way than to add one to the day, handle days at the end of the month, etc.

Cleanest and most Pythonic way to get tomorrow&#39;s date?

How do I get the current date in JavaScript?


Can you please help me in solving this problem. I am trying to order the results of an SQL query by date, but I&#39;m not getting the results I need.

The query I&#39;m using is:

    SELECT date FROM tbemp ORDER BY date ASC


Results are:

    01/02/2009
    03/01/2009
    04/06/2009
    05/03/2009
    06/12/2008
    07/02/2009

Results should be:

    06/12/2008
    03/01/2009
    01/02/2009
    07/02/2009

I need to select the date in the format above. 

Your help is much appreciated.


SQL ORDER BY date problem

Python: I need to show file modification times in the &quot;1 day ago&quot;, &quot;two hours ago&quot;, format.

Is there something ready to do that? It should be in English.


Content Type	Original Author	Original Content on Stackoverflow
Question	user176593	View Question on Stackoverflow
Solution 1 - Mysql	Noah Heldman	View Answer on Stackoverflow
Solution 2 - Mysql	shakirthow	View Answer on Stackoverflow
Solution 3 - Mysql	Kerri	View Answer on Stackoverflow
Solution 4 - Mysql	Pedro Lobito	View Answer on Stackoverflow

Select mysql query between date?

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

Solution 3 - Mysql

Solution 4 - Mysql

Are C# arrays thread safe?

O(log N) == O(1) - Why not?

Attributions