Semantically you are asking “insert Competitors where doesn’t already exist”: INSERT Competitors (cName) SELECT DISTINCT Name FROM CompResults cr WHERE NOT EXISTS (SELECT * FROM Competitors c WHERE cr.Name = c.cName)
9.5 and newer: PostgreSQL 9.5 and newer support INSERT … ON CONFLICT (key) DO UPDATE (and ON CONFLICT (key) DO NOTHING), i.e. upsert. Comparison with ON DUPLICATE KEY UPDATE. Quick explanation. For usage see the manual – specifically the conflict_action clause in the syntax diagram, and the explanatory text. Unlike the solutions for 9.4 and … Read more
Use INSERT … ON DUPLICATE KEY UPDATE QUERY: INSERT INTO table (id, name, age) VALUES(1, “A”, 19) ON DUPLICATE KEY UPDATE name=”A”, age=19