Name number of samples of "bed" object are there in the image No.1098?
samples of "bed" object refer to OBJ_SAMPLE_ID where OBJ_CLASS = 'bed'; image No.1098 refers to IMG_ID = 1098;
SELECT SUM(CASE WHEN T2.OBJ_CLASS = 'bed' THEN 1 ELSE 0 END) FROM IMG_OBJ AS T1 INNER JOIN OBJ_CLASSES AS T2 ON T1.OBJ_CLASS_ID = T2.OBJ_CLASS_ID WHERE T1.IMG_ID = 1098