Oracle sorts the first data

In Oracle sorting, the first data entry needs to update the large unit of the set group. The rule is to obtain the unit information of the first student (minimum set ID. Sort by SUITEID to obtain the first method. Www.2cto.com SQL code UPDATE sim_big_suite u SET u.org _ code = (SELECT SUBSTR (x. pilot_unit, 1, 4) FROM (SELECT n. * FROM sim_student_assign n WHERE n. big_suite_no = 192 AND -- u. big_suite_no = n. big_suite_no AND n. ac_type_code = 14 AND n. fixed_year = '2017 first half 'AND n. train_com = 1001 AND n. position = 'l' order by n. suite_id) x where rownum = 1) WHERE u. ac_type_code = 14 AND u. fixed_year = '2017 first half 'AND u. train_com = 1001;