SQL and booleans, some trivia

Some trivia about SQL and booleans:

SQL 1992 defines three values for a boolean:

<truth value> ::=
      | FALSE
      | UNKNOWN

True booleans aren’t always supported, though. Here’s the truth table of boolean support:

SQL Dialect Supports booleans
DB2 0 (use 1/0 instead)
Derby true (you can safely use true/false)
H2 true
Ingres true
MySQL true
Oracle 0
Postgres true
SQL Server 0
SQLite 0
Sybase ASE 0
Sybase SQL Anywhere 0

Trivia… but nice to know.

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