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PostgreSQL error code

PostgreSQL error 42P02

42P02 is the SQLSTATE PostgreSQL reports for undefined parameter, in class 42, Syntax Error or Access Rule Violation.

SQLSTATE42P02
Condition nameundefined_parameter
Class42 — Syntax Error or Access Rule Violation

Reproduce it, then fix it

$1 is a placeholder that a driver or PREPARE fills in. Pasted into a SQL console, there is nothing to fill it with. Put the value in, or run the query through your driver. Run the broken query to see the error, then switch to the fixed one. Edit either freely; every run is rolled back.

SELECT id, name FROM products WHERE id = $1;
SELECT id, name FROM products WHERE id = 1;

Source: PostgreSQL documentation, Appendix A