String Functions SQL

How to find the length of a string

In this case, let say that we want to print the size or length of a string.

SELECT CITY, LENGTH(CITY) FROM STATION ORDER BY LENGTH(CITY)

LEFT() and RIGHT() functions useful to make substrigns

The LEFT() function extracts a number of characters from a string (starting from left.

Syntax LEFT()

LEFT(string, number_of_chars)

Example: Extract 5 characters from the text in the "CustomerName" column (starting from left):

SELECT LEFT(CustomerName, 5) AS ExtractString
FROM Customers;

now, The RIGHT() function extracts a number of characters from a string (starting from right).

Syntax RIGHT()

RIGHT(string, number_of_chars)

Example Extract 5 characters from the text in the "CustomerName" column (starting from right):

SELECT RIGHT(CustomerName, 5) AS ExtractString
FROM Customers;

CONCAT() function

The CONCAT() function adds two or more expressions together.

Syntax CONCAT()

CONCAT(expression1, expression2, expression3,...)

Example:

SELECT CONCAT(Address, " ", PostalCode, " ", City) AS Address
FROM Customers;

CONCAT_WS() function

The CONCAT_WS() function adds two or more expressions together with a separator.

Syntax CONCAT_WS()

CONCAT_WS(separator, expression1, expression2, expression3,...)

Example

SELECT CONCAT_WS(" ", Address, PostalCode, City) AS Address
FROM Customers;