The following documentation comment has been logged on the website: Page: https://www.postgresql.org/docs/11/static/indexes-unique.html Description:
In https://www.postgresql.org/docs/11/static/indexes-unique.html there are omited clausules For example WHERE clausule is omited. In https://www.postgresql.org/docs/11/static/sql-createindex.html you can see the right sintax with all the clausules.