SQL - REVERSE() Function



The SQL REVERSE() function is used to reverse a string. As result, it shows the last character at the first position and the first character at the last position.

It accepts a string value as a parameter, rearranges the characters in reverse order, and returns the resultant string. If the given string value is NULL, this function returns a NULL value.

Syntax

Following is the syntax of the SQL REVERSE() function −

REVERSE(str);

Parameters

  • str − It is a string to be reversed.

Return value

This function returns a reversed string.

Example

In the following example,we are using the SQL String REVERSE() function to reverse the specified string ‘HelloWorld’.

SELECT REVERSE('HelloWorld');

Output

On executing the above SQL statement, it will produce the following output −

+-----------------------+
| REVERSE('HelloWorld') |
+-----------------------+
| dlroWolleH            |
+-----------------------+

Example

If any of the argument passed to this function is NULL, it returns NULL.

In the following example, we are using the REVERSE() function to reverse the specified string NULL value.

SELECT REVERSE(NULL);

Output

The above SQL query produces the following output −

+------------------------------+
| REVERSE(NULL)                |
+------------------------------+
| NULL                         |
+------------------------------+

Example

In the following example,we are using the REVERSE() function to reverse the pass numeric value '203935132' as an argument to it.

SELECT REVERSE('203935132');

Output

Following is the output of the above query −

+----------------------+
| REVERSE('203935132') |
+----------------------+
| 231539302            |
+----------------------+

Example

You can also pass the column name of a table as an argument to the REVERSE() function to reverse the order of the content of the column. Assume we have created a table in SQL with the name Customers using the CREATE statement as follows: −

CREATE TABLE CUSTOMERS(    
ID INT NOT NULL,    
NAME VARCHAR (20) NOT NULL,    
AGE INT NOT NULL,    
ADDRESS CHAR (25) ,    
SALARY DECIMAL (18, 2));

Now, let's insert four records in to the Customers table using the INSERT statement as shown below −

INSERT INTO CUSTOMERS (ID,NAME,AGE,ADDRESS,SALARY) VALUES (1, 'Ramesh', 32, 'Ahmedabad', 2000.00 ); 
INSERT INTO CUSTOMERS (ID,NAME,AGE,ADDRESS,SALARY) VALUES (2, 'Khilan', 25, 'Delhi', 1500.00 ); 
INSERT INTO CUSTOMERS (ID,NAME,AGE,ADDRESS,SALARY) VALUES (3, 'kaushik', 23, 'Kota', 2000.00 ); 
INSERT INTO CUSTOMERS (ID,NAME,AGE,ADDRESS,SALARY) VALUES (4, 'Chaitali', 25, 'Mumbai', 6500.00 );

The following SQL query rearranges(reverse) the contents of the column NAME in reverse order in the Customers table −

SELECT ID, NAME, REVERSE(NAME) FROM CUSTOMERS;

Output

Following is the output of the above SQL query −

+----+----------+---------------+
| ID | NAME     | REVERSE(NAME) |
+----+----------+---------------+
|  1 | Ramesh   | hsemaR        |
|  2 | Khilan   | nalihK        |
|  3 | kaushik  | kihsuak       |
|  4 | Chaitali | ilatiahC      |
+----+----------+---------------+
sql-string-functions.htm
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