-- (single-line comment)

Available in: DSQL, PSQL

Added in: 1.0

Changed in: 1.5

Description: A line starting with “--” (two dashes) is a comment and will be ignored. This also makes it easy to quickly comment out a line of SQL.

In Firebird 1.5 and up, the “--” can be placed anywhere on the line, e.g. after an SQL statement. Everything from the double dash to the end of the line will be ignored.

Example:

-- a table to store our valued customers in:
create table Customers (
  name varchar(32),
  added_by varchar(24),
  custno varchar(8),
  purchases integer      -- number of purchases
)

Notice that the second comment is only allowed in Firebird 1.5 and up.