I forgot the details. The content is roughly as follows. Two tables with the following content: SQL code + -------- + ------- + ------ + | z_code | mgr | pigs | + -------- + ------- + ------ + | 021 | zhang | 85 | 010 | wang | 70 | + -------- + ------- + ------ + 2 rows in set query final result SQL code + -------- + ------ + ------- + | z_code | city | mgr | + -------- + ------ + ------- + | 010 | BJ | wang | 021 | HB | zhang | + -------- + ------ + ------- + 2 rows in set A table SQL code + ------ + ------- + ------ + | part | mgr | pigs | + ------ + ------- + ------ + | 001 | wang | 20 | 002 | wang | 50 | 011 | zhang | 49 | 012 | zhang | 36 | + ------ + ------- + ------ + 4 the query statement used by the rows in set B table is: SQL code select z_code,. mgr, sum (pigs) pigs from A, B where. mgr = B. mgr group by. mgr order by pigs desc; the following SQL statements are used to create tables and insert statements: SQL code create database pig_store; use pig_store; create table A (z_code varchar (8 ), city varchar (4), mgr varchar (16); create table B (part varchar (8), mgr varchar (16), pigs int (5 )); insert into A values ('010 ', 'bj', 'wang '), ('021', 'hb ', 'zhang '); insert into B values ('001', 'wang', 20), ('002', 'wang', 50), ('011', 'zhang ', 49 ), ('012', 'zhang ', 36); Author: wangtingbang