我的数据库MySQL 中的查询LEFT JOIN 生成了此输出：
mysql> SELECT
LCD,
zonOp,
Codex,
Q,
Codex2,
NumberCode,
CodeDates
FROM
tbl_A A
LEFT JOIN tbl_CB CB ON A.Codex = Codex2
WHERE
(
Q > 0
AND Codex2 IS NOT NULL
AND NumberCode IS NOT NULL
AND CodeDates NOT IN ('0000-00-00')
)
AND zonOp = 'RSID'
GROUP BY
LCD,
NumberCode;
+--------+-------+-------+-------+--------+------------+------------+
| LCD | zonOp | Codex | Q | Codex2 | NumberCode | CodeDates |
+--------+-------+-------+-------+--------+------------+------------+
| RSIDP0 | RSID | XM7 | 0,024 | XM7 | 51015524 | 2014-06-18 |
| RSIDP1 | RSID | XM7 | 1,544 | XM7 | 47266370 | 2014-06-18 |
| RSIDP2 | RSID | XM7 | 0,835 | XM7 | 48742114 | 2014-06-13 |
| RSIDP3 | RSID | XI6 | 0,13 | XI6 | 29721250 | 2014-06-11 |
| RSIDP3 | RSID | XM7 | 0,302 | XM7 | 29721253 | 2013-12-20 |
| RSIDP3 | RSID | XM7 | 0,687 | XM7 | 38680929 | 2014-06-18 |
| RSIDP3 | RSID | XM7 | 0,795 | XM7 | 39415749 | 2014-06-16 |
| RSIDP3 | RSID | XG6 | 0,006 | XG6 | 40240767 | 2014-06-16 |
| RSIDP3 | RSID | XI6 | 0,09 | XI6 | 40240769 | 2014-06-17 |
| RSIDP3 | RSID | XM7 | 0,056 | XM7 | 40240770 | 2014-06-16 |
| RSIDP3 | RSID | XM7 | 0,504 | XM7 | 42624322 | 2014-06-16 |
| RSIDP3 | RSID | XM7 | 0,516 | XM7 | 42797920 | 2014-06-17 |
| RSIDP3 | RSID | XM7 | 0,61 | XM7 | 45180544 | 2014-06-17 |
| RSIDP3 | RSID | XM7 | 0,249 | XM7 | 45494706 | 2014-06-16 |
| RSIDP3 | RSID | XM7 | 0,252 | XM7 | 45541676 | 2014-06-16 |
| RSIDP3 | RSID | XM7 | 0,033 | XM7 | 46309158 | 2014-06-16 |
| RSIDP3 | RSID | XM7 | 0,303 | XM7 | 46348630 | 2014-06-25 |
| RSIDP3 | RSID | XE5 | 0,068 | XE5 | 47542502 | 2014-06-17 |
| RSIDP3 | RSID | XG6 | 0,07 | XG6 | 47542503 | 2014-06-17 |
| RSIDP3 | RSID | XM7 | 0,231 | XM7 | 48541798 | 2014-06-16 |
| RSIDP3 | RSID | XM7 | 0,178 | XM7 | 50230398 | 2013-12-20 |
+--------+-------+-------+-------+--------+------------+------------+
21 rows in set
现在我需要在我的数据库MySQL中提取一个查询LEFT JOIN这个新输出。
标准是，对于列LCD的每个单个值，至少需要1行，最多10行：
+------+-------+------------+
|N_LCD | LCD | NumberCode |
+------+-------+------------+
|1 |RSIDP0 |51015524 |
|1 |RSIDP1 |47266370 |
|1 |RSIDP2 |48742114 |
|1 |RSIDP3 |29721250 |
|2 |RSIDP3 |29721253 |
|3 |RSIDP3 |38680929 |
|4 |RSIDP3 |39415749 |
|5 |RSIDP3 |40240767 |
|6 |RSIDP3 |40240769 |
|7 |RSIDP3 |40240770 |
|8 |RSIDP3 |42624322 |
|9 |RSIDP3 |42797920 |
|10 |RSIDP3 |45180544 |
+------+-------+------------+
我尝试了这个解决方案：
mysql> SELECT
LCD,
zonOp,
Codex,
Q,
Codex2,
NumberCode,
CodeDates
FROM
tbl_A A
LEFT JOIN tbl_CB CB ON A.Codex = Codex2
WHERE
(
Q > 0
AND Codex2 IS NOT NULL
AND NumberCode IS NOT NULL
AND CodeDates NOT IN ('0000-00-00')
)
AND zonOp = 'RSID'
GROUP BY
LCD,
NumberCode
ORDER BY
RAND()
LIMIT 10;
+--------+-------+-------+-------+--------+------------+------------+
| LCD | zonOp | Codex | Q | Codex2 | NumberCode | CodeDates |
+--------+-------+-------+-------+--------+------------+------------+
| RSIDP3 | RSID | XM7 | 0,231 | XM7 | 48541798 | 2014-06-16 |
| RSIDP3 | RSID | XE5 | 0,068 | XE5 | 47542502 | 2014-06-17 |
| RSIDP3 | RSID | XM7 | 0,795 | XM7 | 39415749 | 2014-06-16 |
| RSIDP3 | RSID | XM7 | 0,056 | XM7 | 40240770 | 2014-06-16 |
| RSIDP2 | RSID | XM7 | 0,835 | XM7 | 48742114 | 2014-06-13 |
| RSIDP3 | RSID | XM7 | 0,249 | XM7 | 45494706 | 2014-06-16 |
| RSIDP3 | RSID | XI6 | 0,13 | XI6 | 29721250 | 2014-06-11 |
| RSIDP1 | RSID | XM7 | 1,544 | XM7 | 47266370 | 2014-06-18 |
| RSIDP3 | RSID | XM7 | 0,504 | XM7 | 42624322 | 2014-06-16 |
| RSIDP3 | RSID | XM7 | 0,61 | XM7 | 45180544 | 2014-06-17 |
+--------+-------+-------+-------+--------+------------+------------+
10 rows in set
但新输出是错误的，因为对于LCD值RSIDP0我没有输出而对于LCD值RSIDP3我有8而不是10行。
任何帮助将不胜感激，谢谢你。
我的桌子下面的MySQL。
DROP TABLE IF EXISTS `tbl_A`;
CREATE TABLE `tbl_A` (
`LCD` char(6) DEFAULT NULL,
`NumberCode` int(11) DEFAULT NULL,
`CodeDates` date DEFAULT NULL,
`Codex` char(10) DEFAULT NULL,
`Q` decimal(10,5) DEFAULT NULL,
`zonOp` char(4) DEFAULT NULL,
`ID` int(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`ID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP0', 'RSID', 'XM7', 0.02400, 51015524, '2014-6-18');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP1', 'RSID', 'XM7', 1.54400, 47266370, '2014-6-18');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP2', 'RSID', 'XM7', 0.83500, 48742114, '2014-6-13');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XI6', 0.13000, 29721250, '2014-6-11');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.30200, 29721253, '2013-12-20');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.68700, 38680929, '2014-6-18');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.79500, 39415749, '2014-6-16');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XG6', 0.00600, 40240767, '2014-6-16');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XI6', 0.09000, 40240769, '2014-6-17');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.05600, 40240770, '2014-6-16');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.50400, 42624322, '2014-6-16');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.51600, 42797920, '2014-6-17');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.61000, 45180544, '2014-6-17');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.24900, 45494706, '2014-6-16');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.25200, 45541676, '2014-6-16');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.03300, 46309158, '2014-6-16');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.30300, 46348630, '2014-6-25');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XE5', 0.06800, 47542502, '2014-6-17');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XG6', 0.07000, 47542503, '2014-6-17');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.23100, 48541798, '2014-6-16');
INSERT INTO `tbl_A` (`LCD`, `zonOp`, `Codex`, `Q`, `NumberCode`, `CodeDates`) VALUES ('RSIDP3', 'RSID', 'XM7', 0.17800, 50230398, '2013-12-20');
DROP TABLE IF EXISTS `tbl_cb`;
CREATE TABLE `tbl_cb` (
`Codex2` varchar(3) NOT NULL,
PRIMARY KEY (`Codex2`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
INSERT INTO `tbl_cb` VALUES ('XE5');
INSERT INTO `tbl_cb` VALUES ('XG6');
INSERT INTO `tbl_cb` VALUES ('XI6');
INSERT INTO `tbl_cb` VALUES ('XM7');
INSERT INTO `tbl_cb` VALUES ('XQ7');