What is the equivalent PostgreSQL syntax to Oracle’s CONNECT BY … START WITH?

Use a RECURSIVE CTE in Postgres:

WITH RECURSIVE cte AS (
   SELECT key, value, 1 AS level
   FROM   taxonomy
   WHERE  key = 0

   UNION  ALL
   SELECT t.key, t.value, c.level + 1
   FROM   cte      c
   JOIN   taxonomy t ON t.taxHier = c.key
   )
SELECT value
FROM   cte
ORDER  BY level;

Details and links to documentation in my previous answer:

  • Does PostgreSQL have a pseudo-column like “LEVEL” in Oracle?

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