SELECT raises exception in PL/pgSQL function

Question

I want to implement a loop inside a function but I receive this error:

ERROR query has no destination for result data

The code:<

Answer 1

The manual instructs:

Sometimes it is useful to evaluate an expression or SELECT query but discard the result, for example when calling a function that has side-effects but no useful result value. To do this in PL/pgSQL, use the PERFORM statement:

PERFORM query;

Unless you assign the result, replace

SELECT 1;

with

PERFORM 1;