MySQL roughly random string generation for inserting or updating rows

Ever wanted to inject hashes into new or existing rows of a MySQL database?

Two slightly different methods, but the same result…

Insert

The code below allows you to generate a different hash for each row you’re inserting. You can tweak to choose the string’s length. No unique checks are done.

INSERT INTO table_name (
column_name
) VALUES (
    (SUBSTRING(MD5(RAND()) FROM 1 FOR 20))
)

Update columns and values to suit your needs

Update

The code below allows you to generate a different string for each row affected by the update and choose the random string’s length from 1 to 32 character.

I’m aware it’s not the most random of generators but for url hashes etc, it works well. Be sure to then check for duplicates, which are possible!

Change 20 to a length between 1 and 32 that suits your needs.

Update the WHERE condition to suit your needs

UPDATE table_name
SET column_name = (
    SELECT substring(MD5(RAND()), -20)
)
WHERE condition_column = 1;

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