What is cursor FOR loop explain with example?

The cursor FOR LOOP statement implicitly declares its loop index as a record variable of the row type that a specified cursor returns, and then opens a cursor. With each iteration, the cursor FOR LOOP statement fetches a row from the result set into the record.

How do you make a looping cursor?

Example 2: Cursor For Loop With Inline Cursor.

  1. Directly write the SELECT statement without specifying the cursor name into the loop statement.
  2. Enclose the SELECT statement into parenthesis.
  3. Do not terminate the SELECT statement with a semicolon (;)

What is cursor in PL SQL with examples?

In this chapter, we will discuss the cursors in PL/SQL. Oracle creates a memory area, known as the context area, for processing an SQL statement, which contains all the information needed for processing the statement; for example, the number of rows processed, etc. A cursor is a pointer to this context area.

How can we write cursor in procedure in PL SQL?

To work with cursors you must use the following SQL statements: DECLARE CURSOR. OPEN. FETCH….Cursors in SQL procedures

  1. Declare a cursor that defines a result set.
  2. Open the cursor to establish the result set.
  3. Fetch the data into local variables as needed from the cursor, one row at a time.
  4. Close the cursor when done.

What is Do While loop syntax in PL SQL?

PL/SQL while loop is used when a set of statements has to be executed as long as a condition is true, the While loop is used. The condition is decided at the beginning of each iteration and continues until the condition becomes false….Syntax of while loop:

  • WHILE
  • LOOP statements;
  • END LOOP;

How do you run a loop in SQL?

Syntax

  1. The initial step is executed first, and only once. This step allows you to declare and initialize any loop control variables.
  2. Next, the condition, i.e., initial_value ..
  3. After the body of the for loop executes, the value of the counter variable is increased or decreased.
  4. The condition is now evaluated again.

Why we are using cursor in PL SQL?

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. Cursors are used when the user needs to update records in a singleton fashion or in a row by row manner, in a database table.

Can we write cursor inside procedure?

To use cursors in SQL procedures, you need to do the following:

  • Declare a cursor that defines a result set.
  • Open the cursor to establish the result set.
  • Fetch the data into local variables as needed from the cursor, one row at a time.
  • Close the cursor when done.

How do you write a while loop in SQL?

SQL While loop syntax END; The while loop in SQL begins with the WHILE keyword followed by the condition which returns a Boolean value i.e. True or False. The body of the while loop keeps executing unless the condition returns false. The body of a while loop in SQL starts with a BEGIN block and ends with an END block.

How do you input a loop in PL SQL?

10 LOOP INSERT INTO TAB (col1, col2, col3, col4, col5) VALUES (num1, num2, num3, num4, num5); END LOOP; COMMIT; END; / Enter value for num1: 1 old 2: num1 NUMBER (10) := &num1 new 2: num1 NUMBER (10) := 1; Enter value for num2: 2 old 3: num2 NUMBER (10) := &num2 new 3: num2 NUMBER (10) := 2; Enter value for num3: 3 …

What is the difference between cursor fetch and for loop?

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

  • WHILE LOOP :
  • 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) }
  • DO-WHILE LOOP :

    • How to find Max with a cursor in a loop?

    When you are faced with a data processing decision,determine where you stand with SQL Server cursor usage.

  • If you run into issues with another coding technique and need to get something done quickly,using a cursor may be a viable alternative.
  • If cursors are shunned in your environment,be sure to select another viable alternative.

    • 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

    How to implement a for loop in SQL?

    Usually, we maintain a counter variable that will be incremented or decremented inside the while loop to implement the for loop like functionality using while loop in SQL. The condition is provided in such a way that the execution of statements inside the while loop continues until the value of the counter variable reaches the ending value.