PL/pgSQL Table-Returning Functions — RETURNS TABLE, SETOF and When a View Is Better

A view is the most elegant way to encapsulate a recurring query — right up to the moment the query needs an argument from outside. A view has no parameters. As soon as a value belongs in the WHERE that the caller supplies, the table-valued function is the tool of choice: a function that returns an entire result set … Read more

PL/pgSQL Function Conventions — Volatility, RETURNS and the Boundary to Procedures

A PL/pgSQL function without a volatility marker is VOLATILE by default. That sounds harmless but has a real cost: the planner calls the function again for every row, never pre-computes it once, and excludes it from every functional index. The damage is invisible — until the same query suddenly takes seconds instead of milliseconds. Good PL/pgSQL function conventions start … Read more

Deriving SQL Conventions with Claude Code — the Generate-Refine-Derive Loop

An AI writes you a stored procedure in seconds. It compiles, it runs – and it looks like a stranger wrote it. The next artifact looks different again. Generated SQL is technically correct but stylistically arbitrary – and without an enforced convention, a generated collection drifts apart just like one five developers write by hand. The obvious … Read more

SQL Conventions // PL/pgSQL Procedures You Can Still Read in Two Years

If you write a stored procedure, you write it for someone who doesn’t know it — usually for yourself, 18 months later, at 11 p.m., while an ETL run is stuck. Readability isn’t cosmetics, it’s debugging time. PostgreSQL forces almost nothing on you: names are free, indentation doesn’t matter, a RAISE EXCEPTION swallows any string you assemble inline. That’s exactly … Read more