Space function in SQL Server

Few weeks back, I wrote a blog on CONCAT string function in SQL Server 2012. A user asked if the CONCAT function is similar to Space function in SQL Server and what is the difference between the two functions. I replied to him and clarified the difference of the 2 functions. After that I thought, it would be good to write a blog post on Space function too.

Space function

Space function is useful to return ‘x’ number of spaces, where ‘x’ is an integer.  The syntax for the space function is space(x) where x is an integer. To understand the function lets us look a simple script with and without space function.

Without Space function

The below screen shot displays an output where 2 string values are concatenated without using space function and the resulting string is an output that may not be acceptable. See that the resulting string is a single string without any break between first and last name.

Using Space function

The below screen shot displays an output where 2 string values are concatenated and separated by space function. Using space(1) generated a single space (1 space) and when that is used in the string concatenation, output string is now better and acceptable. 

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SQL Server string function REPLACE with Examples

In this blog we shall learn a string function called REPLACE. We shall use REPLACE function in Select as well as Update statements with examples to understand it better.

We shall start with a basic Select statement using Replace function to understand what it does. 

In simple terms, a REPLACE function takes in a string as first parameter and then accepts a pattern as 2nd parameter, searches for that pattern in the first parameter and replaces with what is passed in the 3rd parameter.

Let us look at an example to understand better. See the below select statement with Replace function. The string value ‘Easy very easy’ is passed as first parameter, then the second parameter ‘EASY’ is passed which is the string pattern, so the Replace functions’ main objective is to find that pattern in the string passed and replace with the value ‘tough’ where ever it sees the string pattern ‘EASY’. Hence it returns ‘tough very tough’ as output. Since there are 2 occurrences of easy in the string.. (see 1st line of the output)

SELECT REPLACE('Easy very easy','EASY','tough')

Note: I ran all queries at once and captured the output, in order to post the results as a single screenshot.

In the next example, we shall see what will happen if we pass an integer values as the 2nd and (or) 3rd parameters. The REPLACE function will still return an output by converting the integer values to character or string values.  (see 2nd line of the output)

SELECT REPLACE('Let us say 123',123,777)

See that 123 was not surrounded by single quotes as ‘123’, but still the function converts it to string value 123. Note, this does not mean that you pass the values without single quotes.

Next, we shall see what happens if one of the parameters is a NULL. If one of the parameters is a NULL value, the output returned will be a NULL. (see 3rd line of the output) 

SELECT REPLACE('In case of nulls',NULL,'Nothing')

Finally, lets look at what happens when you pass a single space as search pattern. 

SELECT REPLACE('Not NULL but Space',' ','BlankSpace')

Since the string value ‘Not NULL but Space’ has 4 single spaces, the output will be enerated by replacing those 4 single spaces with the string value ‘BlankSpace’. (see 4thd line of the output)

Next, let us look at how to use REPLACE function when performing an update to a table data.  Before we update table data, first let us run this query to see how the data looks like.

SELECT TOP 5 EmployeeID, LoginID
FROM HumanResources.Employee

The below is the screenshot when the above query is run..

Now, I would like to replace the value “adventure-works” with “LearnSQLWthBru” in all the rows of the table. So we use Replace function in the “set columnname = expression” in the Update statement, as shown below….

UPDATE AdventureWorks.HumanResources.Employee
SET LoginID = REPLACE(LoginID,'adventure-works','LearnSQLWithBru')

After running this query, re-run the initial select query against the table to see how the data looks after the update.. The pic displayed below is how it looks..

Suggestion: When performing an update against a table, it is a better to run a select statement and include the where clause (to be used in Update statement) to make sure you are going to update as many records as it returns in the select statement.. 

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OFFSET and FETCH – New in SQL Server 2012

In this article we shall learn how to limit the numbers of rows returned by a query using OFFSET and FETCH clause introduced in SQL Server 2012. The following query is executed against AdventureWorks Database.

 SELECT SalesOrderID,SalesOrderDetailID,OrderQty,SpecialOfferID
 FROM [Sales].[SalesOrderDetail]
 ORDER BY SalesOrderDetailID

The following is the query result set when the above T-SQL code is executed.

Observe that the data is displayed sorted by the column SalesOrderDetailID, which is very much clear from the ORDER BY clause at the end of the query. This query will display all records in that table as we have not included any filtering condition.

You might be aware that using TOP clause we can restrict the query result set to as many rows we want it to display. Instead of the top n records, if we wanted to return x number of records from the middle of the result set, sorted on a particular column, we would have to do some additional manipulations and retrieve them. 

In SQL Server 2012, this can be achieved by using the OFFSET and FETCH clause at the end of the Select query, after ORDER BY clause. Let’s take a look at this sample query to understand this better..

 SELECT SalesOrderID,SalesOrderDetailID,OrderQty,SpecialOfferID
 FROM [Sales].[SalesOrderDetail]
 ORDER BY SalesOrderDetailID 

The OFFSET clause sets how many rows needs to be skipped before displaying the result set. In this case we gave OFFSET 5 ROW, so the first 5 rows are skipped. FETCH NEXT x ROW ONLY, displays the next x records, if there are records inside the table. In our example script, we used 10 so 10 rows are displayed. If we mention 10000000 rows, and if there are only 1000 rows in the table, then only 995 rows will be displayed. A small clarification, the keywords ROW or ROWS both will work the same.

Note: Please note that this is correct as of SQL Server 2012 RC0.

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