PERFORM

Executes a query and discards the result (side-effects only).

Category: dynamic-sql

Syntax

PERFORM <query>;

Description

## Overview PERFORM executes a SQL query for its side effects (such as calling functions or checking for row existence) and discards the result set. It is the PL/pgSQL equivalent of running a SELECT when you do not need the returned data. ## Behavior - The query text provided after PERFORM is treated as the body of a SELECT statement. The executor automatically prepends `SELECT ` before execution. - Any PL/pgSQL variable references in the query text are resolved via the SqlResolver before execution, substituting current variable values. - The query executes through DeltaForge's routed SQL execution engine. The result batches are discarded after execution. - The FOUND implicit variable is updated based on whether the query returned any rows. This makes PERFORM useful for existence checks. - PERFORM does not support INTO. To capture results, use a regular SELECT...INTO statement or EXECUTE...INTO. ## Differences from PostgreSQL - Behavior is consistent with PostgreSQL PL/pgSQL. The PERFORM keyword is replaced with SELECT internally, and results are discarded. - Variable resolution uses DeltaForge's SqlResolver, which performs textual substitution. PostgreSQL uses a different internal mechanism for variable binding.

Parameters

Name	Type	Description
`query`		Provide the query body (without the SELECT keyword). The executor prepends SELECT automatically.

Examples

DO $$
BEGIN
  PERFORM 1 FROM employees WHERE id = 42;
  IF FOUND THEN
    PRINT 'Employee 42 exists';
  ELSE
    PRINT 'Employee 42 not found';
  END IF;
END;
$$;

DO $$
DECLARE
  rec RECORD;
BEGIN
  FOR rec IN SELECT table_name FROM information_schema.tables WHERE table_schema = 'public' LOOP
    PERFORM 1 FROM information_schema.columns WHERE table_name = rec.table_name AND column_name = 'updated_at';
    IF FOUND THEN
      PRINT rec.table_name, 'has updated_at column';
    END IF;
  END LOOP;
END;
$$;

DO $$
BEGIN
  PERFORM set_config('app.current_user', 'pipeline_runner', true);
  PRINT 'Config set';
END;
$$;

DO $$
DECLARE
  order_id INT := 1001;
BEGIN
  PERFORM 1 FROM orders WHERE id = order_id AND status = 'shipped';
  IF NOT FOUND THEN
    RAISE EXCEPTION 'Order % is not shipped', order_id;
  END IF;
END;
$$;

Pitfalls

Do not include the SELECT keyword in the query. PERFORM prepends SELECT automatically, so `PERFORM SELECT ...` would produce `SELECT SELECT ...`, which is a syntax error.
PERFORM cannot capture results. Use SELECT...INTO or EXECUTE...INTO if you need the returned values.
FOUND is updated by PERFORM but can be overwritten by the next SQL statement. Check FOUND immediately after PERFORM.