SQL Server Word Sound Comparison

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As we learned in a previous post, you can use the SOUNDEX function to understand the sound that a word makes. You can then compare it to another word to see if the sound matches. This works okay for exact sound matches. But what if you want check to see if the word sound similar to another word? And how do you find out how similar the words are? SQL Server has you covered. In SQL Server 2005 they released the DIFFERENCE function.

 
The DIFFERENCE Function
When you use the SOUNDEX function in SQL Server, it returns a 4 character code that represents the sound of the word. The DIFFERENCE function compares two of these 4 character codes and returns a value between 0 and 4. The return value indicates how many of these characters in the 4 character code were the same. Here is an example:

[table colwidth=”100|100″ width=”200″ colalign=”left|left”]
Word,SOUNDEX Code
Frog,F620
Blog,B420
[/table]

DIFFERENCE: 2

You can see in the example above that if you compare the SOUNDEX code of the two words, only 2 characters are identical. The ‘F’ is different from the ‘B’. The ‘6’ is different from the ‘4’. But the ‘2’ and the ‘0’ are the same between the two codes. Thus… the difference is 2.

 
Put It All Together
Now that you understand how SOUNDEX and DIFFERENCE work, you can use them to create searches that are based on “sounding like a word”. Here is an example… remember, 0 means the words sound nothing alike and 4 means that the words sound exactly alike. In my example, I am going to match on a likeness of 3… which is sounding pretty similar.

DECLARE	@NameToCheckFor	VARCHAR(50)

SET	@NameToCheckFor = 'donky'

SELECT	AnimalName
FROM	Animal
WHERE	DIFFERENCE(AnimalName, @NameToCheckFor) >= 3

 
 
Reference: http://msdn.microsoft.com/en-us/library/ms188753.aspx

SOUNDEX – Discovering The Sounds Of Words In SQL Server

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Let’s face it, not everyone is a perfect speller all the time. Exact match queries are pretty easy to do in SQL Server. But, what if you wanted to correct their spelling or search based on a misspelled word? How is this possible? In SQL Server 2008+ you have the ability to do this with the SOUNDEX function.

SOUNDEX
The SOUNDEX function will take an input word and convert it in to a 4 character code representing the sound of the word. For example: goat -> G300.

So what does this 4 character code mean? The first character represents the first character in the string, the rest of the characters represent the rest of the characters in the string. Of course SQL Server does some magic to come up with this code. If you are interested more in the makeup of this code, see the MSDN link at the bottom of this post. Essentially, this 4 character code represents the sound of the word.

 
How To Use It
You can use this just like any other function in SQL Server.

SELECT	SOUNDEX('dog') AS SoundOfDog

An easy way to search based on word sound would be something like this:

SELECT	*
FROM	Animal
WHERE	SOUNDEX(AnimalName) = SOUNDEX('dug')

The above query would find words like “dog”, “dig”, “dag”

 
Reference: http://msdn.microsoft.com/en-us/library/ms187384.aspx

How To Create A Date Table

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Many times when developing SQL Server databases you have the requirement to show all dates in a range. One way to do this is with a date table. One of the most common reasons that I use a date table is when I have a reconciliation report. In a reconciliation report I want to show all of the days in a date range, even if they don’t have data on those days. SQL Server doesn’t have a function to generate dates in a range. So to accomplish this, I create a date table using the following script.

CREATE
TABLE	DateTable
		(DateValue	DATETIME)

GO

DECLARE @StartDate		DATETIME = '01/01/2014'
DECLARE @NumberOfDays	INT = 3000

INSERT
INTO	DateTable
		(DateValue)
SELECT	DATEADD(DAY, RowNum, @StartDate) AS DateValue
FROM	(SELECT	TOP (@NumberOfDays)
				p1.PARAMETER_ID,
				ROW_NUMBER() OVER (ORDER BY p1.PARAMETER_ID) - 1 AS RowNum
		 FROM	sys.all_parameters p1
		 CROSS	JOIN sys.all_parameters p2) NumberTable

 

What Is SQL Server

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What Is SQL Server
SQL Server is a database management system (DBMS) produced by Microsoft. The purpose of SQL Server is to store and retrieve data for use in computer applications. These applications could be mobile apps, web sites, desktop applications, or more.

Data in SQL Server is stored in tables. These tables have rows and columns, much like you would see in an Excel spreadsheet. SQL Server accesses this data using a coding language called T-SQL (Transact-SQL). This code is called a query. Here is a sample query that pulls all of the data from a table.

SELECT	*
FROM	AnimalTable

 
Easiest Definition Of “What Is SQL Server”
SQL Server is a program built by Microsoft that other programs can use to store and retrieve data.

SQL Server Synonyms – What They Are And How To Use Them

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What Is A Synonym?

A synonym in SQL Server can be thought of like having another name for a table.  The table doesn’t even have to be in your own database.  The intent of having synonyms is for an easy way to reference objects in another database.  It basically gives you a short alias to call server objects that live in another database.  You can create a synonym for tables, views, stored procedures, and functions!

 
Example Without Synonym:

SELECT	*
FROM	FarmAnimals.dbo.SoundsOfAnimals

 
Example With Synonym:

SELECT	*
FROM	AnimalSounds

In the example above, the synonym AnimalSounds represents FarmAnimals.dbo.SoundsOfAnimals.

 
NOTE: Because the synonym is basically an alias for a different server object, INSERT, UPDATE, SELECT, DELETE operations happen directly on the base table and not on the synonym.

 
Why Would You Use A Synonym?

There are 2 main reasons for using synonyms.  The first reason is to make the code a little easier to read.  It makes all of the remote objects look like local objects.  The second reason is that it creates a layer of abstraction.  If the base table changes, then you only need to change the synonym.  If you did not use a synonym, then you would need to go in to every stored procedure, view, function, etc… and change the reference to the new table.

 
Real-Life Use

So… although it is a neat concept, I really don’t use synonyms very much.  The one application where I see it very useful is when you do not own the database that you are referencing (like if you bought a 3rd party product).  Product updates could change the table/stored procedure names… if you use a synonym to reference the database tables, then it would only take 1 change on your side to get your program working again.

 
 
Reference:  http://msdn.microsoft.com/en-us/library/ms187552.aspx