Syntax of for-loop in SQL Server

In SQL Server, the FOR loop is used for iterating over a range of numbers or through a result set. However, it is not a native feature in SQL Server like in traditional programming languages such as JavaScript or Python. Instead, you would typically use a WHILE loop for iteration in SQL Server.

To illustrate how a loop would work, here is an example of how you can simulate a FOR loop in SQL Server using a WHILE loop:

Syntax:

DECLARE @counter INT = 1;   -- Initializing counter

DECLARE @max INT = 10;      -- Set your upper limit

WHILE @counter <= @max

BEGIN

    -- Your loop logic goes here, such as printing values or performing operations

    PRINT 'Current counter value: ' + CAST(@counter AS VARCHAR(10));

    -- Increment the counter

    SET @counter = @counter + 1;

END

Key Points:

• Initialization: You declare a variable to initialize the starting point (@counter in this example).
  
• Condition: The loop continues to execute as long as the condition (@counter <= @max) is true.
  
• Increment: The counter is incremented to avoid an infinite loop.
  
• Loop Body: Inside the loop, you can include any SQL operations you need to perform, like selecting, updating, or inserting data.
  

Alternatives:

• Cursors: If you need to iterate through a result set, you can use cursors in SQL Server, which is a more efficient method for row-by-row operations.
  
• Set-based operations: SQL is primarily set-based, and often, it's better to solve problems with set operations rather than looping.