Interestingly, boolean types have been introduced only late in the SQL standard, namely in SQL:1999. Even today, not all databases natively support BOOLEAN or BIT types. Most importantly, we can still wait for them in Oracle for a while. Here's "Ask Tom"'s point of view from 2002 on the subject: https://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:6263249199595 Oracle. Why U No … Continue reading The JDBC Boolean Compatibility List
Some trivia about SQL and booleans: SQL 1992 defines three values for a boolean: <truth value> ::= TRUE | FALSE | UNKNOWN True booleans aren't always supported, though. Here's the truth table of boolean support: SQL DialectSupports booleansDB20 (use 1/0 instead)Derbytrue (you can safely use true/false)H2trueHSQLDBtrueIngrestrueMySQLtrueOracle0PostgrestrueSQL Server0SQLite0Sybase ASE0Sybase SQL Anywhere0 Trivia... but nice to know.