SQL: best way to store yes/no values? Looking after performance in huge databases

Question

I have some columns where I have to store basically yes/no values. For example user status for active or inactive. Newsletter suscription status for suscribed or unsuscribed.

Well I want to know (considering tables with a lot of records) if the best way is to put a tiny int with char length of 1 and set 1 for yes, and 0 for no.

Is this a correct thought? Or there are no impact in the performance of db queries when using just words like yes, no, active, inactive, suscribed, etc.

thanks in advance.

Answer 1

Semantically, I suggest you use bit if it's available to you. When looking at the column, any other developer can immediately determine that a boolean value is stored in it. If you don't have bit, try using tinyint. Ensuring that 1 is the only true value and 0 is the only false value will bring consistency. Otherwise, you could end up with a messy mixture of true/false, yes/no, valid/invalid, y/n, and/or t/f.

Comparing bit or tinyint values probably isn't slower than comparing strings, and even if it were slower than comparing strings, I can't imagine it having a significant effect on overall speed.