What is difference between loop and cursor?

What is difference between loop and cursor?

Cursors in sql server allow you to fetch a set of data, loop through each record, and modify the values as necessary; then, you can easily assign these values to variables and perform processing on these values. While loop also same as cursor to fetch set of data and process each row in sql server.

Is there a way to loop in SQL?

In SQL Server, there is no FOR LOOP. However, you simulate the FOR LOOP using the WHILE LOOP.

What is alternative for cursor in SQL Server?

Temporary tables have been in use for a long time and provide an excellent way to replace cursors for large data sets. Just like table variables, temporary tables can hold the result set so that we can perform the necessary operations by processing it with an iterating algorithm such as a ‘while’ loop.

Which is better WHILE loop or cursor?

Always confusing thing is which one is better; SQL While loop or cursor? While SQL While loop is quicker than a cursor, reason found that cursor is defined by DECLARE CURSOR. Every emphasis of the loop will be executed inside system memory and consuming required server assets.

What is cursor in SQL Server with example?

A SQL cursor is a database object that retrieves data from result sets one row at a time. The cursor in SQL can be used when the data needs to be updated row by row. A SQL cursor is a database object that is used to retrieve data from a result set one row at a time.

What are SQL loops?

The LOOP statement executes a sequence of statements within a PL/SQL code block multiple times. WHILE statement (PL/SQL) The WHILE statement repeats a set of SQL statements as long as a specified expression is true. The condition is evaluated immediately before each entry into the loop body.

How do you execute a loop in SQL Server?

I am detailing answer on ways to achieve different types of loops in SQL server.

  1. FOR Loop. DECLARE @cnt INT = 0; WHILE @cnt < 10 BEGIN PRINT ‘Inside FOR LOOP’; SET @cnt = @cnt + 1; END; PRINT ‘Done FOR LOOP’;
  2. DO.. WHILE Loop.
  3. REPEAT..UNTIL Loop.

Why do we need cursor in SQL?

In SQL procedures, a cursor make it possible to define a result set (a set of data rows) and perform complex logic on a row by row basis. By using the same mechanics, an SQL procedure can also define a result set and return it directly to the caller of the SQL procedure or to a client application.

What is the difference between cursor fetch and for loop?

So with open fetch you can use dynamic cursors but with for loop you can define normal cursor without declaration.

What is a cursor in SQL and why do you need it?

The ‘Cursor’ is the PL/SQL construct that allows the user to name the work area and access the stored information in it. The major function of a cursor is to retrieve data, one row at a time, from a result set, unlike the SQL commands which operate on all the rows in the result set at one time.

What is a cursor in SQL?

Cursor is a Temporary Memory or Temporary Work Station. It is Allocated by Database Server at the Time of Performing DML(Data Manipulation Language) operations on Table by User. Cursors are used to store Database Tables. There are 2 types of Cursors: Implicit Cursors, and Explicit Cursors.

How do you create a cursor in SQL?

– Most Common SQL Server Cursor Syntax – SQL Server Cursor as a Variable – SQL Server Cursor as Output of a Stored Procedure – SQL Server Cursor Current Of Example – SQL Server Cursor Alternative with a WHILE Loop

Are SQL Server cursors good or bad?

SQL Server cursors are notoriously bad for performance. In any good development environment people will talk about cursors as if they were demons to be avoided at all costs. The reason for this is plain and simple; they are the best way to slow down an application.

Is while loop better than cursor?

Sometimes the justification is that constructing a while loop is simpler and more straightforward than constructing a cursor. Others suggest that a while loop is faster than a cursor because, well, it isn’t a cursor. Of course the underlying mechanics still represent a cursor, it’s just not explicitly stated that way using DECLARE CURSOR.

All loops have 3 components : initialization,condition,updation.

  • Recognized by keyword ‘while’.
  • The condition variable should be already initialized.
  • Takes in account only condition part
  • Updation is done inside the loop (else,it becomes an infinite loop).
  • Syntax :
  • while ( condition) {//code with updation (if required) }