MySQL Functions (Usefull in Programming)

I am running on MySql 3.23.58 version

1 . Concat the String
SELECT CONCAT('My', 'S', 'QL');
-> MySQL
-----------

2. Concat with Word Separator
SELECT (CONCAT_WS(",","First name","Second name","Last Name")) as fullname;
-> First name,Second name,Last Name
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3. String Length
SELECT LENGTH('text');
->4
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3. String Padding (Add characters to string)
String must contin 4 character long if 1st_expr is not contain 4
charater then add 3rd_expr to String.
SELECT LPAD('hi',4,'..');
-> '..hi'
SELECT RPAD('hi',4,'..');
-> 'hi'
-----------

4. String Padding (Add character to string)
SELECT LEFT('foobarbar', 5);
->'fooba'
SELECT RIGHT('foobarbar', 5);
->'arbar'

COMBINATION OF 3 & 4 Point
SELECT RPAD(LEFT('foobarbar', 5),8,'.') as str;
-> fooba...

## Miscellaneous Functions

SELECT DATABASE();
-> current Working databse

SELECT USER();
-> curent User

SELECT SUBSTRING_INDEX(USER(),"@",1);
-> Concat userstring

SELECT VERSION();
->Current Mysql version

SELECT CONNECTION_ID();
-> Current connectio Id