CONCAT function in Oracle

CONCAT is one of the vital string/char functions of Oracle. It is used to concatenate two strings together. The CONCAT function is supported in the various versions of the Oracle/PLSQL, including, Oracle 12c, Oracle 11g, Oracle 10g, Oracle 9i and Oracle 8i.
Syntax 1: To concatenate two strings.

CONCAT( string1, string2 )


Syntax 2: To concatenate more than two strings.

SELECT CONCAT (CONCAT ( string1, string2 ), string3)
FROM dual;


Parameters:
String1: : It is used to specify the first string to concatenate.
String2: : It is used to specify the second string to concatenate.
String3: : It is used to specify the third string to concatenate.

Example 1: Concatenation of two strings.

CONCAT (‘HELLO’, ‘ WORLD’)

Output:

 ‘HELLO WORLD’


Explanation:
The two strings are concatenated as one string.

Example 2: Concatenation of more than two strings.

SELECT CONCAT( CONCAT (‘HELLO’, ‘ MY’), ' FRIENDS') FROM dual;

Output:

 ‘HELLO MY FRIENDS’


Explanation:
All the three strings are concatenated as one string.

Example 3: Concatenation of strings with single quotes.

SELECT CONCAT( CONCAT (‘LET’‘S’, ‘ BE’), ' FRIENDS') FROM dual;

Output:

 ‘LET’S BE FRIENDS’


Explanation:
All the three strings are concatenated as one string.