Length Function - How to get Data of String in Bytes in MySQL

Understanding String Length in Bytes with MySQL's Length Function

The "Length" function in MySQL serves the purpose of calculating the size of a string in terms of bytes. Think of it as a way to determine how much space a string occupies in memory. This function is quite similar to the "DataLength" function found in SQL Server.

Here's the basic syntax for using the Length function:
SELECT LENGTH('StringValue');
For a more practical example, let's consider a scenario where we have a "customer" table containing various records, and we're interested in finding out the data length for the "firstname" and "lastname" values.

To set the stage, here's how you could create the "customer" table:
CREATE TABLE `customer` (
  `idcustomer` int, 
  `firstname` varchar(50)  NULL,
  `lastname` varchar(30)  NULL,
  `age` int(11) DEFAULT NULL,
  `phonenumber` char(11) DEFAULT NULL,
  `dob` date DEFAULT NULL,
  `gender` char(1) NOT NULL
-- Now let's insert some sample records
INSERT INTO customer(idcustomer, firstname, lastname, age, phonenumber, dob, gender)
(1, 'Raza', null, 39, '505-4141969', '1980-01-01', 'M'),
(2, 'Aamir', 'Naz', 39, '505-4141969', '1980-01-01', 'M'),
-- ... (other records here)
Now, if you're curious about how much space the values in the "firstname," "lastname," and "phonenumber" columns occupy, you can utilize the Length function like this:
  firstname, LENGTH(firstname) AS firstname_length,
  lastname, LENGTH(lastname) AS lastname_length,
  phonenumber, LENGTH(phonenumber) AS phonenumber_length
FROM customer;
By using the Length function, you can gain insights into the byte size of the data stored in these columns.

In essence, this tutorial has covered the concept of determining column size using the Length function in MySQL. It's a handy tool when you need to work with string data and understand their memory consumption.
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