The LEFT function returns the specified number of characters from the left of a given string. Its functionality is the same in both MSSQL and MySQL.
Syntax:
LEFT(String, n)
Where string is the string to retrieve leftmost characters from, and n is the number of characters to retrieve.
Example:
select LEFT('This is demo',3)
----------------------
Thi

It's similar to the MSSQL LEFT function.
Example:
mysql> select LEFT('This is demo',3);
+------------------------+
| LEFT('This is demo',3) |
+------------------------+
| Thi |
+------------------------+
