postgres=#
postgres=#
postgres=# -- Unique constraint refers to a group of columns, the columns are listed separated by commas:
postgres=#
postgres=# CREATE TABLE example (
postgres(# a integer,
postgres(# b integer,
postgres(# c integer,
postgres(# UNIQUE (a, c)
postgres(# );
NOTICE: CREATE TABLE / UNIQUE will create implicit index "example_a_key" for table "example"
CREATE TABLE
postgres=#
postgres=# drop table example;
DROP TABLE
postgres=#