Firebird simply has SQL, which is very close to standard SQL (probably closer than MySQL), it then discerns a number of different variants:
- SQL, the basic variant (although some of the old InterBase documentation seems to use this to refer to ESQL as well)
- ESQL (or Embedded SQL) which allows use of SQL directly in code (using a preprocessor), not used much these days
- DSQL (or Dynamic SQL), this is what you usually use when executing queries against Firebird from a programming language
- PSQL (or Procedural SQL) is the extension for stored procedures, stored functions, triggers and execute block