issue when executing the pgsql complaining about loop - arrays

Question

create or replace function f() RETURNS void AS
declare
tableArray text[] := '{"ADDRESS","CONSISTENCY_CHECK","DEPARTMENT_SUPERVISION"}';
tableName CHARACTER VARYING;
value INTEGER ;
BEGIN
FOREACH tableName IN ARRAY tableArray
LOOP
select user_id from tableName where user_id=2631;
if found then
update tableName set user_id=2651 where user_id=2631;
delete from tableName where user_id=2631;
END loop;
end;
here is the error that I get when trying to execute the pgplsql: ERROR syntax error at or near "loop"

Answer 1

There are more issues:
the body of function should be string - you can use apostrophes or more usual and practical $$ custom string separators.
the result of SELECT should not be lost. The clause INTO is missing.
table name should not be a variable - variable cannot be used as table name. In this case you need dynamic SQL - EXECUTE statement.
camel notation for variable names should not be used for SQL language, that is case insensitive
CREATE OR REPLACE FUNCTION f()
RETURNS void AS $$
DECLARE
table_array text[] := '{"ADDRESS","CONSISTENCY_CHECK","DEPARTMENT_SUPERVISION"}';
table_name text;
value integer ;
rc integer
BEGIN
FOREACH table_name IN ARRAY table_array
LOOP
EXECUTE format('SELECT * FROM %I WHERE user_id = $1', table_name) USING 2631;
-- variable FOUND cannot be used for dynamic SQL
GET DIAGNOSTICS rc = ROW_COUNT;
IF rc > 0 THEN
EXECUTE format('UPDATE %I SET user_id = $1 WHERE user_id = $2', table_name) USING 2651, 2631;
EXECUTE format('DELETE %I WHERE user_id = $1', table_name) USING 2631;
END IF;
END LOOP;
END;
$$ LANGUAGE plpgsql;