Syntax error at or near "WHERE"

Question

While creating postgres function it is resulting an error as

ERROR: syntax error at or near "WHERE" LINE 19: WHERE s.shift_id = shiftid ^ ********** Error **********

ERROR: syntax error at or near "WHERE" SQL state: 42601 Character: 108

Please Help..

CREATE OR REPLACE FUNCTION shiftwisedata_sp(INOut shiftid bigint,InOut userdate date,OUT shift_name character varying (50),OUT from_time character varying(50),OUT to_time character varying(50),OUT cal bigint)
  RETURNS SETOF record AS
$BODY$
  BEGIN
return query
SELECT userdate, s.shift_name, 
          ('00:00' + (h.hour  * interval '1Hour'):: time) AS from_time,
          ('00:00' + ((h.hour + 1)  * interval '1Hour'):: time) AS to_time,
          COALESCE(r.Readings, 0) AS readings
   FROM   shift_wise s
   CROSS  JOIN (VALUES(0), (1), (2), (3), (4), (5), (6), (7), (8), (9),
                      (10), (11), (12), (13), (14), (15), (16), (17), (18), (19),
                      (20), (21), (22), (23)) AS h(hour)
   LEFT JOIN LATERAL (SELECT SUM(r.param_value) AS Readings
                 FROM   table_1 r
                 WHERE  r.timestamp_col >= CAST(userdate as timestamp without time zone ) + h.hour  * interval '1Hour'
                   AND  r.timestamp_col < CAST(userdate as timestamp without time zone ) + h.hour + 1 * interval '1Hour'
                   ) AS r 
WHERE s.shift_id = shiftid
 AND (s.to_time > s.from_time              AND 
       h.hour >= date_part(HOUR, s.from_time) AND
       h.hour <  date_part(HOUR, s.to_time) 
    OR
      s.to_time < s.from_time AND
         (h.hour >= date_part(HOUR, s.from_time) OR
          h.hour < date_part(HOUR, s.to_time))
       )
      ORDER BY s.to_time;
	
  END;
$BODY$
  LANGUAGE plpgsql VOLATILE

Answer 1

looks like the syntax error is LEFT JOIN needs an ON clause before the WHERE