PL/SQL Program to Print Table of a Number

A common exercise for learning any new programming language is to print a multiplication table (e.g., the "5 times table"). This is a perfect task for learning how to use loops and print formatted output in PL/SQL.

This simple guide will show you the basic concepts and a complete program to solve this problem.

What You Need to Know

To write this program, you will use a few basic PL/SQL concepts:

1. Enabling Output: You must run this command once in your SQL tool (like SQL*Plus or SQL Developer) to see the printed results:SET SERVEROUTPUT ON;
2. Anonymous Block: We will write our code in a DECLARE...BEGIN...END; block.
3. Variables: We'll need a variable to hold the number for which we want to print the table (e.g., n NUMBER := 7;).
4. FOR Loop: We will use a loop to iterate from 1 to 10 (or any other number you choose) to create the table.
5. Printing the Result: We use DBMS_OUTPUT.PUT_LINE() inside the loop to print each line.
6. Concatenation (||): We'll use the || operator to build a nicely formatted string for each line of the table.

PL/SQL Program: Print a Multiplication Table

This program will print the multiplication table for the number stored in the n variable, from 1 to 10.

PL/SQL Program

SET SERVEROUTPUT ON;

DECLARE
  -- The number for which to print the table
  n NUMBER := 8;

BEGIN
  -- We don't need to declare 'i'.
  -- The FOR loop automatically creates it as an integer.
  
  -- Loop from 1 to 10
  FOR i IN 1..10 LOOP
  
    -- Print each line of the table by joining the strings and
    -- calculating the result (n * i) inside the statement.
    DBMS_OUTPUT.PUT_LINE(
      n || ' x ' || i || ' = ' || (n * i)
    );
    
  END LOOP;
END;
/

Result (for n := 8)

8 x 1 = 8
8 x 2 = 16
8 x 3 = 24
8 x 4 = 32
8 x 5 = 40
8 x 6 = 48
8 x 7 = 56
8 x 8 = 64
8 x 9 = 72
8 x 10 = 80

Program Explanation

1. DECLARE section: We create one variable, n, and assign it the value 8. This is the number our table will be based on.
2. BEGIN section: The program's logic starts.
3. FOR i IN 1..10 LOOP: This is our loop. It will run 10 times.
   • The first time, i will be 1.
   • The second time, i will be 2.
   • ...and so on, until i is 10.
4. DBMS_OUTPUT.PUT_LINE(...): This line runs inside the loop. It builds and prints a new string every time the loop iterates.
5. n || ' x ' || i || ' = ' || (n * i): This is the string concatenation.
   • When i is 1, it builds: '8' || ' x ' || '1' || ' = ' || (8 * 1), which becomes '8 x 1 = 8'.
   • When i is 2, it builds: '8' || ' x ' || '2' || ' = ' || (8 * 2), which becomes '8 x 2 = 16'.
   • This continues until the loop finishes at i = 10.
6. END LOOP;: This signals the end of the loop block.
7. END; and /: This signals the end of the PL/SQL program and tells the SQL tool to execute it.