Create an Array with a dynamic Query in PL/pgSQL

Question

I am trying to create an array with a dynamic select query in a plpgsql function. Unfortunately I get an syntax error.

ERROR:  syntax error at or near "EXECUTE"
ZEILE 19:  SELECT DISTINCT INTO outputIdsToDelete ARRAY( EXECUTE findA...
                                                         ^

Can somebody help me please? Here is the function itself:

CREATE OR REPLACE FUNCTION deleteMAPPINGs(
   mapTable1_key text, mapping_table text, mapTable2_key text,
   table2 text, table2_key text,
   inputIdsToDelete bigint[]) RETURNS bigint[] AS
$BODY$
DECLARE
    outputIdsToDelete bigint[];
    findAllQuery text;
    findUnreferencedQuery text;
    BEGIN
    findAllQuery := 'SELECT DISTINCT ' || mapTable2_key ||
        ' FROM '  || mapping_table ||
        ' WHERE ' || mapTable1_key || ' = ANY(inputIdsToDelete)';
    findUnreferencedQuery := 'SELECT DISTINCT ' || table2_key || --find unused
        ' FROM ' || table2 ||
        ' WHERE ' || table2_key || ' NOT IN (' ||
            'SELECT DISTINCT ' || mapTable2_key || --all used
            ' FROM ' || mapping_table || ')';

    SELECT DISTINCT INTO outputIdsToDelete ARRAY( EXECUTE findAllQuery );

    DELETE FROM mapping_table WHERE 
        mapTable1_key = ANY(inputIdsToDelete) AND
        mapTable2_key = ANY(outputIdsToDelete);

    SELECT DISTINCT INTO outputIdsToDelete --overwrite with unused
        ARRAY(EXECUTE findUnreferencedQuery);

    RETURN outputIdsToDelete;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;

Answer 1

You cannot use EXECUTE inside SQL statement - EXECUTE is only plpgsql statement, so it cannot be inside SQL -

EXECUTE string INTO variable