There are a number of String Manipulation Functions built into most SQL Environments, Here are several of the more popular Functions for MySQL
CONCAT()
CONCAT_WS()
LTRIM()
RTRIM()
TRIM()
LENGTH()
LOCATE()
LEFT()
RIGHT()
SUBSTRING()
SUBSTRING_INDEX()
REPLACE()
INSERT()
REVERSE()
LOWER()
UPPER()
LPAD()
RPAD()
SPACE()
REPEAT()
Merge Strings Together
Divide Strings Up
White Space & Delimiter Control
Change the String
Query the String