mysql> select * from test
-> ;
+----+------------+-------+-----------+
| id | name | score | subject |
+----+------------+-------+-----------+
| 1 | xiaoming | 89 | shuxue |
| 2 | xiaohong | 89 | shuxue |
| 3 | xiaohong | 80 | english |
| 4 | xiaohong | 80 | physics |
| 5 | xiaohong | 80 | astronaut |
| 6 | xiaoming | 80 | physics |
| 7 | xiaoming | 80 | astronaut |
| 8 | xiaoming | 80 | english |
| 9 | xiaobai | 80 | astronaut |
| 10 | 1.2xiaobai | 80 | english |
| 11 | 2.2xiaobai | 80 | physics |
| 12 | 3xiaobai | 80 | shuxue |
| 13 | 123xiaohei | 80 | astronaut |
| 14 | xiaohei | 80 | shuxue |
| 15 | xiaohei | 80 | physics |
| 16 | .12xiaohei | 80 | english |
+----+------------+-------+-----------+
16 rows in set (0.00 sec)
mysql> select * from user;
+------+----------+-----------+
| id | name | address |
+------+----------+-----------+
| 1 | xiaoming | beijing |
| 2 | xiaobai | shandong |
| 3 | xiaohong | suzhou |
| 4 | xiaohei | changchun |
+------+----------+-----------+
4 rows in set (0.00 sec)
mysql> select id,name from user where name="xiaohong" union select id,name from test where name="xiaoming";
+------+----------+
| id | name |
+------+----------+
| 3 | xiaohong |
| 1 | xiaoming |
| 6 | xiaoming |
| 7 | xiaoming |
| 8 | xiaoming |
+------+----------+
5 rows in set (0.00 sec)
mysql> select id,name from user where name="xiaohong" union all select id,name from test where name="xiaoming";
+------+----------+
| id | name |
+------+----------+
| 3 | xiaohong |
| 1 | xiaoming |
| 6 | xiaoming |
| 7 | xiaoming |
| 8 | xiaoming |
+------+----------+
5 rows in set (0.00 sec)
mysql> select id,name from user where name="xiaohong" union all select id,name from test where name="xiaoming" order by id;
+------+----------+
| id | name |
+------+----------+
| 1 | xiaoming |
| 3 | xiaohong |
| 6 | xiaoming |
| 7 | xiaoming |
| 8 | xiaoming |
+------+----------+
5 rows in set (0.00 sec)
