# Rails 3+ :
```ruby
Movie.where(&#39;release &gt; ?&#39;, DateTime.now)
```
---
# Pre Rails 3
```ruby
Movie.where([&#39;release &gt; ?&#39;, DateTime.now])
```



In recent versions of rails, you can do this:

```
User.where(created_at: 3.days.ago..Time.now)
```

See some other examples here: https://stackoverflow.com/a/24150094

## Update

Rails core team decided to revert this change for a while, in order to discuss it in more detail. See [this comment](https://github.com/rails/rails/pull/39613#issuecomment-659553274) and [this PR](https://github.com/rails/rails/pull/39863) for more info.

I am leaving my answer only for educational purposes.

---

## new &#39;syntax&#39; for comparison in Rails 6.1 (Reverted)

```ruby
Movie.where(&#39;release &gt;&#39;: DateTime.now)
```

Here is [a link to PR](https://github.com/rails/rails/pull/39613) where you can find more examples.

In Ruby 2.7, you can try this:

```
License.where(expiration: Time.zone.today..)
```

```
SELECT &quot;licenses&quot;.* FROM &quot;licenses&quot; WHERE &quot;licenses&quot;.&quot;expiration&quot; &gt;= &#39;2021-07-06 15:12:05&#39;
```

I have a function that returns same kind of objects (query results) but with no properties or methods in common. In order to have a common type I resorted using an empty interface as a return type and &quot;implemented&quot; that on both. 

That doesn&#39;t sound right of course. I can only console myself by clinging to hope that someday those classes will have something in common and I will move that common logic to my empty interface. Yet I&#39;m not satisfied and thinking about whether I should have two different methods and conditionally call next. Would that be a better approach? 

I&#39;ve been also told that .NET Framework uses empty interfaces for tagging purposes. 

My question is: is an empty interface a strong sign of a design problem or is it widely used? 

**EDIT**: For those interested, I later found out that discriminated unions in functional languages are the perfect solution for what I was trying to achieve. C# doesn&#39;t seem friendly to that concept yet. 

**EDIT**: I wrote a [longer piece][1] about this issue, explaining the issue and the solution in detail.


  [1]: https://hackernoon.com/are-interfaces-code-smell-bd19abc266d3#.dvyk5m4ge

Are empty interfaces code smell?

I&#39;m trying to access a class constant in one of my classes:

    const MY_CONST = &quot;value&quot;;

If I have a variable which holds the name of this constant like this:

    $myVar = &quot;MY_CONST&quot;;

Can I access the value of MY_CONST somehow?

    self::$myVar

does not work obviously because it is for static properties.
Variable variables does not work either.

Accessing a class constant using a simple variable which contains the name of the constant

Trying to search where movies coming out have a release date greater than today&#39;s date

     Movie.where(&#39;release &gt; ?&#39;, Date.today)
    ActiveRecord::StatementInvalid: Mysql::ParseError: You have an error in your SQL     syntax;    check the manual that corresponds to your MySQL server version for the right syntax to use near &#39;release &gt; &#39;2011-09-25&#39;)&#39; at line 1: SELECT `movies`.* FROM `movies` WHERE (release &gt; &#39;2011-09-25&#39;)




Rails where date is greater than given date query

Trying to search where movies coming out have a release date greater than today's date
<pre><code class="hljs language-sql"> Movie.where('release > ?', Date.today)
ActiveRecord::StatementInvalid: Mysql::ParseError: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'release > '2011-09-25')' at line 1: SELECT `movies`.* FROM `movies` WHERE (release > '2011-09-25')
</code></pre>

I need to subtract 1 month and 4 days with mysql, I saw the command
`DATE_ADD (NOW (), - 1 MONTH)` perfect for 1 month but for 1 month and 4 days, using 31 days is not valid for every month that some bring 30, 29, 28. I can not add 31 + 4, 30 + 4, etc.


Subtract month and day mysql

Please clarify two things for me:

1. Can a Foreign key be NULL?
2. Can a Foreign key be duplicate?

As fair as I know, `NULL` shouldn&#39;t be used in foreign keys, but in some application of mine I&#39;m able to input `NULL` in both Oracle and SQL Server, and I don&#39;t know why.

Can a foreign key be NULL and/or duplicate?

I&#39;m trying to find the rows that are in one table but not another, both tables are in different databases and also have different column names on the column that I&#39;m using to match.

I&#39;ve got a query, code below, and I think it probably works but it&#39;s way too slow:

    SELECT `pm`.`id`
    FROM `R2R`.`partmaster` `pm`
    WHERE NOT EXISTS (
    	SELECT * 
    	FROM `wpsapi4`.`product_details` `pd`
    	WHERE `pm`.`id` = `pd`.`part_num`
    )

So the query is trying to do as follows:

Select all the ids from the R2R.partmaster database that are not in the wpsapi4.product_details database. The columns I&#39;m matching are partmaster.id &amp; product_details.part_num

Select from one table where not in another

How would I do something like this?

&lt;pre&gt;
SQL SELECT row FROM table WHERE id=max(id)
&lt;/pre&gt;

How do I select an entire row which has the largest ID in the table?

My lower level knowledge of SQL (Server 2008) is limited, and is now being challanged by our DBAs. Let me explain (I have mentioned obvious statements in the hope that I am right, but if you see something wrong, please tell me) the scenario:

We have a table which holds &#39;Court Orders&#39; for people. When I created the table, (Name: CourtOrder), I created it like:

    CREATE TABLE dbo.CourtOrder
    (
      CourtOrderID INT NOT NULL IDENTITY(1,1), (Primary Key)
      PersonId INT NOT NULL,
      + around 20 other fields of different types.
    )

I then applied a non-clustered index to the primary key (for efficiency). My reasons is that it is a unique field (primary key), and should be indexed, mainly for selection purposes, as we often `Select from table where primary key = ...`

I then applied a CLUSTERED index on PersonId. The reason was to group orders for a particular person physically, as the vast majority of work is getting orders for a person. So, `select from mytable where personId = ...`

I have been pulled up on this now. I have been told that we should put the clustered index on the primary key, and the normal index on the personId. That seems very strange to me. First off, why would you put a clustered index on a unique column? what is it clustering? Surely that&#39;s a waste of the clustered index? I&#39;d have believed a normal index would be used on a unique column. Also, clustering the index would mean we can&#39;t cluster a different column (One per table, right?).

The reasoning for me being told I have made a mistake is that they believe putting a clustered index on the PersonId would make inserts slow. For the 5% gain in speed of a select, we would be getting a 95% degradation in speed on inserts and updates. Is that correct and valid?

They say that because we cluster the personId, SQL Server has to rearrange data when ever we insert or make a change to the PersonId.

So then I have asked, why would SQL have the concept of a CLUSTERED INDEX, if it&#39;s so slow? Is it as slow as they&#39;re saying? How should I have setup my indexes to achieve optimum performance? I&#39;d have thought SELECT is used more than INSERT... but they say that we&#39;re having locking issues on INSERTS...

Hope someone can help me.

Clustered vs Non-Clustered

I have a particularly complex model with validations and callbacks defined. The business needs now calls for a particular scenario where adding a new record requires skipping the validations and callbacks. What&#39;s the best way to do this?

Rails 3 skip validations and callbacks

The command line version of &#39;httparty&#39; with basic authentication works simple and great:

    httparty -u username:password http://example.com/api/url

But now I&#39;m looking for the way I can add the basic auth to a HTTParty.get call from within a Rails app. First of all, for testing purposes, I want to hard code the login credentials in the Controller. Just to make sure it works. But I can&#39;t find any documentation or examples how you can pass these along.

A HTTParty.get without credentials works fine:

    @blah = HTTParty.get(&quot;http://twitter.com/statuses/public_timeline.json&quot;)

But I don&#39;t see how I can make a variation on this that accepts the *-u username:password* part.

The next challenge for me (am very new to Ruby/Rails) is to get the user credentials from a user form and pass it along dynamically, but most important for me now it to get the hard coded version to work.


How to use basic authentication with httparty in a Rails app?

Right now if I run my test suite using `rake spec` I get an error:

&lt;pre&gt;
1) SegmentsController GET &#39;index&#39; should work
   Failure/Error: get &#39;index&#39;
   undefined method `locale&#39; for #&lt;User:0x0000012a6bc490&gt;
   # ./spec/controllers/segments_controller_spec.rb:14:
      in `block (3 levels) in &lt;top (required)&gt;&#39;
&lt;/pre&gt;

This is normal as I do have an error :)

The problem is that the trace isn&#39;t very helpful. I know it broke in `segments_controller_spec.rb`, line 14, but this is just where I call the test:

    ### segments_controller_spec.rb:14
    get &#39;index&#39;

I would prefer to have the actual line breaking and the complete trace, not the part in the spec folder.

Running with `--trace` doesn&#39;t help.

How to get rspec-2 to give the full trace associated with a test failure?

Is there a way to comment out a chunk of highlighted code?

I am programming in ruby, and I hate putting # on lines individually.

Block commenting in Gedit?

I keep getting

     @controller is nil: make sure you set it in your test&#39;s setup method.

When I run my tests. Any idea what this means?

Content Type	Original Author	Original Content on Stackoverflow
Question	Mike	View Question on Stackoverflow
Solution 1 - Sql	Adam Eberlin	View Answer on Stackoverflow
Solution 2 - Sql	Patrick	View Answer on Stackoverflow
Solution 3 - Sql	Marian13	View Answer on Stackoverflow
Solution 4 - Sql	José Mateus	View Answer on Stackoverflow

Rails where date is greater than given date query

Sql Problem Overview

Sql Solutions

Solution 1 - Sql

Rails 3+ :

Pre Rails 3

Solution 2 - Sql

Solution 3 - Sql

Update

new 'syntax' for comparison in Rails 6.1 (Reverted)

Solution 4 - Sql

Accessing a class constant using a simple variable which contains the name of the constant

Are empty interfaces code smell?

Attributions