>>They were introduced in SQL-99 - you probably blocked that memory, as this was the SQL that added official support for boolean data type - sticking it to Oracle and DB2 ;-))
>
>SQL Server doesn't have boolean data type either

True. But at least they tried to offer something in that area that a) needed less space than tinyint or char
b) at least steered their users to a "common usage" IN the product.

Compare Oracle citing that you can use [0,1] ["Y","N"].["T","F"], which will lead to code perhaps sprinkled with different codings. To top it of, the following would also work:
[0,10] ["1","0"].["t","f"],["H","I"]...
I know, I am somewhat biased with Oracle...
DB2 usually gets more of a smile and less of a frown from me, but dumbing down bought smaller DB (I think it was Derby) to make it more compatible with DB2 ? Not a move I applaud.