MySQL Boolean "tinyint(1)" holds values up to 127?

mysql boolean tinyint
JD Isaacks picture JD Isaacks · Dec 9, 2010 · Viewed 52k times · Source

I wanted to make a true/false field for if an item is in stock.

I wanted to set it to Boolean ( which gets converted to tinyint(1) ), 1 for in stock, 0 for not in stock.

I am getting feeds from vendors, so I thought to myself, "What if they pass how many are instock?"

So I wondered if I inserted a number higher than 1 what would happen. I assumed it would default to 1.

To my surprise it will allow me to hold any number up to 127, anything over defaults to 127.

Can anyone explain why?

Answer

BoltClock picture BoltClock · Dec 9, 2010

The signed TINYINT data type can store integer values between -128 and 127.

However, TINYINT(1) does not change the minimum or maximum value it can store. It just says to display only one digit when values of that type are printed as output.

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