mySql function return nothing

Question

I'm creating this function that supposed to return a random string:

create function createRandomString() returns Text
        return concat( 
        char(round(rand()*25)),
        char(round(rand()*25)),
        char(round(rand()*25)),
        char(round(rand()*25)),
        char(round(rand()*25)),
        char(round(rand()*25)),
        char(round(rand()*25)),
        char(round(rand()*25))
    );

For some reason this function return nothing... i don't know why..

When i'm using the exact same concat() inside a select - it works.

Gordon Linoff · Accepted Answer · 2013-11-03 17:52:38Z

1

The problem is that you are returning numeric values between 0 and 25, which are not normal characters to put into a string. Add 65 to them to start at 'A':

create function createRandomString() returns Text
        return concat( 
        char(round(rand()*25+65)),
        char(round(rand()*25+65)),
        char(round(rand()*25+65)),
        char(round(rand()*25+65)),
        char(round(rand()*25+65)),
        char(round(rand()*25+65)),
        char(round(rand()*25+65)),
        char(round(rand()*25+65))
    );

You might want to read up on ASCII coding as well, so you better understand what you are doing.

answered Nov 3, 2013 at 17:52

Gordon Linoff

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