Reverse a string in PL/SQL

Prerequisite – PL/SQL introduction

In PL/SQL code groups of commands are arranged within a block. A block group related declarations or statements. In declare part, we declare variables and between begin and end part, we perform the operations.

Given a string, the task is to reverse a string using PL/SQL.

Examples:

Input: skeegrofskeeg
Output: geeksforgeeks

Input: geeks
Output: skeeg

Approach:

• Find the length of the string.
• Then traverse the string in a reverse manner.
• Store the characters in another string.
• Print the final string.

Below is the required implementation:

DECLARE
    -- declare variable str , len
    -- and str1 of datatype varchar
    str  VARCHAR(20) := 'skeegrofskeeg';
    len  NUMBER;
    str1 VARCHAR(20);
BEGIN
    -- Here we find the length of string
    len := Length(str);

    -- here we starting a loop from max len to 1
    FOR i IN REVERSE 1.. len LOOP
        -- assigning the reverse string in str1
        str1 := str1
                || Substr(str, i, 1);
    END LOOP;

    dbms_output.Put_line('Reverse of string is '
                         || str1);
END;
-- Program End

Output :

Reverse of string is geeksforgeeks