🔤 String Functions in SQL

Last Updated: Jan 2026

It Help To Work With Text Data In SQL.

Most Common String Functions

LENGTH()

  • Returns the number of characters in a string.
SELECT LENGTH('Hello World');

UPPER()

  • Converts a string to uppercase.
SELECT UPPER('hello world');

LOWER()

  • Converts a string to lowercase.
SELECT LOWER('HELLO WORLD');

CONCAT()

  • Concatenates two or more strings into a single string.
SELECT CONCAT('Hello', ' ', 'World');

SUBSTRING()

  • Extracts a substring from a string.
/*
SUBSTRING(string, start, end)
*/

SELECT SUBSTRING('Hello World', 1, 5);

-- Output: Hello

LEFT()

  • Returns the leftmost characters of a string.
/*
LEFT(string, no_of_characters)
*/

SELECT LEFT('Hello World', 5);

-- Output: Hello

RIGHT()

  • Returns the rightmost characters of a string.
/*
RIGHT(string, no_of_characters)
*/

SELECT RIGHT('Hello World', 5);

-- Output: World

REPLACE()

  • Replaces a substring in a string with another substring.
/*
REPLACE(string, old_substring, new_substring)
*/

SELECT REPLACE('Hello World', 'World', 'Universe');

-- Output: Hello Universe

INSTR()

  • Returns the position of the first occurrence of a substring in a string.
/*
INSTR(string, substring)
*/

SELECT INSTR('Hello World', 'World');

-- Output: 6

Trim()

  • Removes leading and trailing spaces from a string.
/*
TRIM(string)
*/

SELECT TRIM('   Hello World   ');

-- Output: Hello World

CONCAT_WS()

  • Concatenates multiple strings with a separator.
/*
CONCAT_WS(separator, string1, string2, ...)
*/

SELECT CONCAT_WS(' ', 'Hello', 'World');

-- Output: Hello World

LPAD()

  • Adds padding to the left of a string.
/*
LPAD(string, total_length, padding_character)
*/

SELECT LPAD('Hello', 10, '*');

-- Output: ***Hello

RPAD()

  • Adds padding to the right of a string.
/*
RPAD(string, total_length, padding_character)
*/

SELECT RPAD('Hello', 10, '*');

-- Output: Hello***
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