Skip to main content

Restrict the number of rows affected in SQL Server

By

Introduction:
In my previous article I have explained about  how to Get number of affected rows in sql. In  this article I will explain about how to restrict the number of rows affected in  sql server.

Explanation:
To restrict the number of rows affected by sql server  SET ROWCOUNT is used. It Causes SQL Server to stop processing the query after the specified number of rows are returned.

Syntax:
SET ROWCOUNT { number | @number_var }

Arguments:
number | @number_var

Is the number, an integer, of rows to be processed before stopping the specific query.

The setting of the SET ROWCOUNT option is ignored for INSERT, UPDATE, and DELETE statements against remote tables and local and remote partitioned views.
To set this option off so that all rows are returned, specify SET ROWCOUNT 0
Setting the SET ROWCOUNT option causes most Transact-SQL statements to stop processing when they have been affected by the specified number of rows. This includes triggers and data modification statements such as INSERT, UPDATE, and DELETE. The ROWCOUNT option does not affect dynamic cursors, but it does limit the rowset of keyset and insensitive cursors. This option should be used with caution and primarily with the SELECT statement.

SET ROWCOUNT overrides the SELECT statement TOP keyword if the rowcount is the smaller value.


SET ROWCOUNT is ignored in INSERT, UPDATE, and DELETE statements when an explicit TOP expression is used in the same statement. This includes statements in which INSERT is followed by a SELECT clause.
The setting of SET ROWCOUNT is set at execute or run time and not at parse time.

Examples:
SET ROWCOUNT stops processing after the specified number of rows. In the following example, note that 545 rows meet the criteria of Quantity less than 300. However, from the number of rows returned by the update, you can see that not all rows were processed. ROWCOUNT affects all Transact-SQL statements.

USE AdventureWorks;
GO
SELECT count(*) AS Count
FROM Production.ProductInventory
WHERE Quantity < 300;
GO
Here is the result set.
Count       
----------- 
537          
(1 row(s) affected)


 
Now, set ROWCOUNT to 4 and update all rows with a Quantity less than 300.
SET ROWCOUNT 4;
UPDATE Production.ProductInventory
SET Quantity = 400
WHERE Quantity < 300;
GO
(4 row(s) affected)

Do you like this article. Then share with your friends. Or like our Facebook page. Or post your comments below…
Labels:

Comments

Post a Comment

Popular posts from this blog

Code To Convert rupees(numbers) into words using C#.Net

By
Introduction: In my previous article I have explained about how to validate emailid using javascript . In this article I am going to explain about code used to convert rupees(numbers) into words using C#.Net . Explanation: For explanation purpose I have a page. It has a textbox to input the numbers. And when you click on the convert to words button then it will convert the input numbers into words and shows it in the below label. Below is the C# code used to do this functionality. public static string NumbersToWords( int inputNumber) {     int inputNo = inputNumber;     if (inputNo == 0)         return "Zero" ;     int [] numbers = new int [4];     int first = 0;     int u, h, t;     System.Text. StringBuilder sb = new System.Text. StringBuilder ();     if (inputNo < 0)     { ...
16 comments
Read More...

C# Extension Methods Example

By
In this article i am going to explain about Extension Methods  with example. Extension methods enable you to "add" methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type. Extension methods are a special kind of static method, but they are called as if they were instance methods on the extended type. For client code written in C# and Visual Basic, there is no apparent difference between calling an extension method and the methods that are actually defined in a type. If you do implement extension methods for a given type, remember the following points: An extension method will never be called if it has the same signature as a method defined in the type. Extension methods are brought into scope at the namespace level. For example, if you have multiple static classes that contain extension methods in a single namespace named Extensions, they will all be brought into scope by the using Extensions; directive. ...
Post a Comment
Read More...

VBScript equivalent string functions in C#.Net

By
C# Method VBScript Description IndexOf() InStr Returns the position of the first occurrence of one string within another. The search begins at the first character of the string - InStrRev Returns the position of the first occurrence of one string within another. The search begins at the last character of the string ToLower() LCase Converts a specified string to lowercase SubString() Left Returns a specified number of characters from the left side of a string Length() Len Returns the number of characters in a string TrimStart() LTrim Removes spaces on the left side of a string TrimEnd() RTrim Removes spaces on the right side of a string Trim() Trim Removes spaces on both the left and the right side of a string SubString() M...
Post a Comment
Read More...