What is the storage overhead in using VARCHAR in MySQL

What is the storage overhead in using VARCHAR in MySQL

Answer:

MySQL allow VARCHAR to have length from a value from 0 to 65,535.

Since MySQL need to store the length of each VARCHAR field, in additional to the actual data itself, it needs 16 bits = 2 bytes for each field. But if the length of VARCHAR during table creation is less than or equal to 255, it only take 1 byte per field.

Reference: http://dev.mysql.com/doc/refman/5.1/en/char.html

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