Following string functions can be use only with string as input parameter and returns either string or numeric in output.
1. ASCII -> Returns ASCII value of leftmost character from string
2. CHAR -> Converts ASCII value to character
3. CHARINDEX -> Returns position of search expression or character from string
4. DIFFERENCE -> Returns difference between two string either 4 for least difference or 0 for highest difference.
5. LEFT -> Returns number of character from left side.
6. LEN -> Returns length of the string value
7. LOWER -> Returns string in lower case
8. LTRIM -> Remove space starting from left side
9. NCHAR -> Convert normal character to Unicode character.
10. PATINDEX ->Returns position of first occurrence of character in string
11. QUOTENAME ->Returns valid string with delimiter
12. REPLACE -> It replaces old string with new string
13. REPLICATE -> It will repeats string specific number of times.
14. REVERSE -> It displays the string in reverse order.
15. RIGHT -> It returns right part of the string with specified number of character.
16. RTRIM -> Removes space from right side of the string
17. SOUNDEX -> Returns four character to identify the similarity
18. SPACE -> Adds extra space in the string
19. STR -> Converts character data in numeric
20. STUFF ->Insert string into another string
21. SUBSTRING -> Returns part of character string
22. UNICODE -> Converts into UNICODE character
23. UPPER -> Converts string into upper case