mysql Tinyint as unsigned

Question

I tried to write t=t|128 but got an out of range error. I suspect tinyint is signed. However http://dev.mysql.com/doc/refman/5.5/en/numeric-types.html says it may be unsigned (b

Answer 1

Firstly, you should do something with negative values, otherwise ALTER TABLE...UNSIGNED will throw an error. For example you could increase all values -

UPDATE table SET tiny_field = tiny_field + 128;

Then use ALTER TABLE to change field type/option.