Simone
CREATE TABLE A (
`C1` VARCHAR(10),
`C2` VARCHAR(10),
`C3` VARCHAR(10),
`C4` VARCHAR(10),
`C5` INT
);
INSERT INTO A
SELECT '华北', '辽宁', '沈阳', '20020202', 2 UNION ALL
SELECT '华东', '山东', '青岛', '18020133', 3 UNION ALL
SELECT '华北', '北京', '北京', '7193', 7 UNION ALL
SELECT '华北', '北京', '北京', '8358', 5 UNION ALL
SELECT '华北', '北京', '北京', '9773', 8 UNION ALL
SELECT '华东', '山东', '青岛', '18020133', 5 ;
CREATE TABLE B (
`C1` VARCHAR(10),
`C2` VARCHAR(10),
`C3` VARCHAR(10),
`C4` VARCHAR(10),
`C5` INT
);
INSERT INTO B
SELECT '华北', '辽宁', '沈阳', '20020202', 5 UNION ALL
SELECT '华东', '山东', '青岛', '18020133', 6 UNION ALL
SELECT '华北', '北京', '北京', '7193', 2 UNION ALL
SELECT '华东', '甘肃', '兰州', '7364', 3 UNION ALL
SELECT '华东', '湖北', '武汉', '7512', 7 UNION ALL
SELECT '华东', '湖北', '武汉', '7512', 2 UNION ALL
SELECT '华东', '江苏', '常州', '7582', 5 UNION ALL
SELECT '华东', '江苏', '淮安', '7670', 7;
SELECT
IFNULL(A.`C1`, B.`C1`) AS `区域`,
IFNULL(A.`C2`, B.`C2`) AS `省份`,
IFNULL(A.`C3`, B.`C3`) AS `城市`,
IFNULL(A.`C4`, B.`C4`) AS `编码`,
SUM(A.`C5`) AS `表A销量`,
SUM(B.`C5`) AS `表B销量`
FROM
A LEFT JOIN B
ON (
A.`C1` = B.`C1` AND
A.`C2` = B.`C2` AND
A.`C3` = B.`C3` AND
A.`C4` = B.`C4`
)
GROUP BY
IFNULL(A.`C1`, B.`C1`),
IFNULL(A.`C2`, B.`C2`),
IFNULL(A.`C3`, B.`C3`),
IFNULL(A.`C4`, B.`C4`)
UNION
SELECT
IFNULL(A.`C1`, B.`C1`) AS `区域`,
IFNULL(A.`C2`, B.`C2`) AS `省份`,
IFNULL(A.`C3`, B.`C3`) AS `城市`,
IFNULL(A.`C4`, B.`C4`) AS `编码`,
SUM(A.`C5`) AS `表A销量`,
SUM(B.`C5`) AS `表B销量`
FROM
A RIGHT JOIN B
ON (
A.`C1` = B.`C1` AND
A.`C2` = B.`C2` AND
A.`C3` = B.`C3` AND
A.`C4` = B.`C4`
)
GROUP BY
IFNULL(A.`C1`, B.`C1`),
IFNULL(A.`C2`, B.`C2`),
IFNULL(A.`C3`, B.`C3`),
IFNULL(A.`C4`, B.`C4`);
+------+------+------+----------+---------+---------+
| 区域 | 省份 | 城市 | 编码 | 表A销量 | 表B销量 |
+------+------+------+----------+---------+---------+
| 华北 | 辽宁 | 沈阳 | 20020202 | 2 | 5 |
| 华北 | 北京 | 北京 | 7193 | 7 | 2 |
| 华北 | 北京 | 北京 | 8358 | 5 | NULL |
| 华北 | 北京 | 北京 | 9773 | 8 | NULL |
| 华东 | 山东 | 青岛 | 18020133 | 8 | 12 |
| 华东 | 甘肃 | 兰州 | 7364 | NULL | 3 |
| 华东 | 湖北 | 武汉 | 7512 | NULL | 9 |
| 华东 | 江苏 | 常州 | 7582 | NULL | 5 |
| 华东 | 江苏 | 淮安 | 7670 | NULL | 7 |
+------+------+------+----------+---------+---------+
9 rows in set (0.00 sec)
你是要查前十个查询结果中相同的那些记录，而不求前十个相同记录吧，因为这是有差别的，按照你的语句，应该是求前者，即先求出A的前十条数据，B的前十条数据，再求它们的交集。
既然是求交集，那么这两个表的关系模式应该是相同的了，
select a.* from
(select * from table order by table.a desc limit 10) as a, (select * from table order by table.b desc limit 10) as b
where a.primary_key = b.primary_key --先将两个结果作为两张临时表，然后通过主键 primary_key来获取交集（交集肯定就是主键相等的了，因为关系模式相同）
