The document provides an overview of SQL string functions used for string manipulation, detailing various functions such as initcap(), upper(), lower(), length(), trim(), lpad(), rpad(), concat(), replace(), reverse(), and ascii(). Each function is accompanied by example SQL queries to illustrate its usage. These functions facilitate operations like changing case, trimming spaces, padding strings, concatenating, and replacing substrings in SQL.

2. String
Functions in SQL
•SQL string functions are used primarily for string
manipulation.

3. •Employee
SELECT * FROM employee;

4. • The initcap() function converts the first letter of each word in a string
to upper case, and converts any remaining characters in each word
to lowercase.
Query: SELECT initcap(ename) FROM employee;
Initcap(
)

5. • UCASE () is a synonym for UPPER ().
Returns the string str with all characters changed to uppercase according to
the current character set mapping.
Query: SELECT UPPER(ename) FROM employee;
UPPER(str)/UCASE(s
tr)

6. * LCASE () is a synonym for LOWER ().
* Returns the string str with all characters changed to lowercase
according to the current character set mapping.
Example1: SELECT lower(ename) from employee ;
LOWER(str)/ LCASE(str)

7. * Returns the length of the string str measured in bytes. A multi-byte
character counts as multiple bytes. This means that for a string
containing five two-byte characters,
LENGTH() returns 10, whereas CHAR_LENGTH() returns 5.
Query: SELECT LENGTH('ename') from employee ;
LENGTH(str)

8. • Returns the string str with all remstr prefixes or suffixes removed. If
none of the specifiers BOTH, LEADING, or TRAILING is given,
BOTH is assumed. remstr is optional and, if not specified, spaces
are removed.
Example: SELECT TRIM(‘ reena ') from dual;
TRIM
([{BOTH | LEADING | TRAILING} [remstr] FROM] str)/
TRIM([remstr FROM] str)

9. Example: SELECT TRIM(LEADING ‘#' FROM ‘###reena###') from
dual;
TRIM
{LEADING}

10. Example: SELECT TRIM(BOTH ‘#' FROM ‘###reena###') from dual;
TRIM {BOTH}

11. Example: SELECT TRIM(TRAILING ‘#' FROM ‘###reena###');
TRIM
{TRAILING}

12. • Returns the string str with trailing space characters removed.
Example: SELECT RTRIM(‘muskan ') from dual;
RTRIM(str)

13. • Returns the string str with leading space characters removed.
Example: SELECT LTRIM(‘ muskan') from dual;
LTRIM(str)

14. • Returns the string str, left-padded with the string pad str to a length of len
characters. If str is longer than len, the return value is shortened to len
characters.
Example: SELECT LPAD(‘11',4,’22') from dual;
LPAD(str,len,padstr)

15. • Returns the string str, right-padded with the string pad str to a length of len
characters. If str is longer than len, the return value is shortened to len
characters.
Example: SELECT RPAD(‘11’,4, ‘22') from dual;
RPAD(str,len,padstr)

16. • Returns the string that results from concatenating the arguments. May have
one or more arguments. If all arguments are non-binary strings, the result is
a non-binary string. If the arguments include any binary strings, the result is
a binary string. A numeric argument is converted to its equivalent binary
string form; if you want to avoid that, you can use an explicit type cast, as in
this:
Example : SELECT CONCAT( ename, hire_date) FROM employee;
CONCAT (str1,str2,...)

17. • Returns the string str with all occurrences of the string from_str replaced by
the string to_str. REPLACE() performs a case-sensitive match when
searching from_str.
Example: SELECT REPLACE(‘RRR.com', ‘R', ‘Rr’) from dual;
REPLACE(str,from_str,to_st
r)

18. • Returns the string str with the order of the characters reversed.
Example: SELECT REVERSE('abcd') from dual;
REVERSE(str)

19. • Returns the numeric value of the leftmost character of the string str. Returns
0 if str is the empty string. Returns NULL if str is NULL. ASCII() works for
characters with numeric values from 0 to 255.
Example: SELECT ASCII('2') FROM DUAL;
ASCII(str)