https://www.postgresql.org/docs/devel/sql-insert.html#id-1.9.3.152.9
Insert a distributor, or do nothing for rows proposed for insertion when an > existing, excluded row (a row with a matching constrained column or columns > after before row insert triggers fire) exists. Example assumes a unique > index has been defined that constrains values appearing in the did column: > Suggesting this as replacement: Insert a distributor, or do nothing if the proposed row conflicts with an existing row. Per-row triggers BEFORE INSERT are fired, and possible effects on the proposed applied, before checking for conflicts. Example assumes a unique index on the did column exists: Regards Erwin
