String Function

CONCAT(str1,str2,...) :

Returns the string that results from concatenating the arguments.

example 1 :
SELECT CONCAT('My', 'S', 'QL'); // 'MySQL'.
LTRIM(str) :

Remove leading spaces

example 1 :
Select LTRIM(' abcd') //abcd
RTRIM(str) :

Remove trailing spaces

example 1 :
Select RTRIM('abcd ') //abcd .
FIND_IN_SET(str,strlist) :

Returns a value in the range of 1 to N if the string str is in the string list strlist consisting of N substrings. A string list is a string composed of substrings separated by "," characters. If the first argument is a constant string and the second is a column of type SET, the FIND_IN_SET() function is optimized to use bit arithmetic. Returns 0 if str is not in strlist or if strlist is the empty string. Returns NULL if either argument is NULL. This function does not work properly if the first argument contains a comma (",") character.

example 1 :
SELECT FIND_IN_SET('b','a,b,c,d'); //2