MySQL: 按特定顺序连接两个表的不同行？

Question

我有一份我想要的库存单位和销售交易清单，(1) 按单位 SKU 加入，(2) 按日期以先进先出的顺序将一项交易关联到一个库存单位.我在第二部分遇到问题。

我能想到的最好的是：

SELECT `units`.`unit_date`, `units`.`unit_id`, `trans`.`tran_date`, `trans`.`tran_id`, `units`.`unit_sku` FROM `units`
    INNER JOIN `trans`
        ON `trans`.`unit_sku` = `units`.`unit_sku`
GROUP BY `trans`.`tran_id`, `trans`.`unit_sku`
ORDER BY `units`.`unit_date` asc, `trans`.`tran_date` asc
;

units table:

unit_date  | unit_id | unit_sku
2015-06-01 | 1       | U1KLM
2015-06-02 | 2       | U1KLM
2015-06-03 | 3       | U2QRS
2015-06-04 | 4       | U2QRS
2015-06-05 | 5       | U1KLM

trans table:

tran_date  | tran_id | unit_sku
2015-06-11 | A       | U2QRS
2015-06-12 | B       | U1KLM
2015-06-13 | C       | U1KLM
2015-06-14 | D       | U2QRS
2015-06-15 | E       | U1KLM

想要的结果 是一个 tran_id 与 unit_sku 中的一个 unit_id 按从早到晚的顺序加入unit_date:

unit_date  | unit_id | tran_date  | tran_id | unit_sku
2015-06-01 | 1       | 2015-06-12 | B       | U1KLM
2015-06-02 | 2       | 2015-06-13 | C       | U1KLM
2015-06-03 | 3       | 2015-06-11 | A       | U2QRS
2015-06-04 | 4       | 2015-06-14 | D       | U2QRS
2015-06-05 | 5       | 2015-06-15 | E       | U1KLM

查询（不需要的）结果仅将tran_id连接到最早出现的unit_sku的unit_id：

unit_date  | unit_id | tran_date  | tran_id | unit_sku
2015-06-01 | 1       | 2015-06-12 | B       | U1KLM
2015-06-01 | 1       | 2015-06-13 | C       | U1KLM
2015-06-01 | 1       | 2015-06-15 | E       | U1KLM
2015-06-03 | 3       | 2015-06-11 | A       | U2QRS
2015-06-03 | 3       | 2015-06-14 | D       | U2QRS

关于如何获得预期结果的任何想法？在此设置中，只有 unit_date 和 tran_date 是 sortable；其余随机生成。

复制脚本：

DROP TEMPORARY TABLE IF EXISTS `units`;
DROP TEMPORARY TABLE IF EXISTS `trans`;
CREATE TEMPORARY TABLE `units` (`unit_date` date, `unit_id` char(1) , `unit_sku` char(5), PRIMARY KEY(`unit_id`));
CREATE TEMPORARY TABLE `trans` (`tran_date` date, `tran_id` char(1) , `unit_sku` char(5), PRIMARY KEY(`tran_id`));

INSERT INTO `units` (`unit_date`, `unit_id`, `unit_sku`) VALUES
    ('2015-06-01', '1', 'U1KLM')
    , ('2015-06-02', '2', 'U1KLM')
    , ('2015-06-03', '3', 'U2QRS')
    , ('2015-06-04', '4', 'U2QRS')
    , ('2015-06-05', '5', 'U1KLM')
;

INSERT INTO `trans` (`tran_date`, `tran_id`, `unit_sku`) VALUES
    ('2015-06-11', 'A', 'U2QRS')
    , ('2015-06-12', 'B', 'U1KLM')
    , ('2015-06-13', 'C', 'U1KLM')
    , ('2015-06-14', 'D', 'U2QRS')
    , ('2015-06-15', 'E', 'U1KLM')
;

SELECT `units`.`unit_date`, `units`.`unit_id`, `trans`.`tran_date`, `trans`.`tran_id`, `units`.`unit_sku` FROM `units`
    INNER JOIN `trans`
        ON `trans`.`unit_sku` = `units`.`unit_sku`
GROUP BY `trans`.`tran_id`, `trans`.`unit_sku`
ORDER BY `units`.`unit_date` asc, `trans`.`tran_date` asc
;

Answer 1

我相信这就是您要找的：（这是假设 1 对 1 的关系）

SET @UNITRN := 0;
SET @TRANSRN :=0;
SELECT A.`unit_date`, A.`unit_id`, B.`tran_date`, B.`tran_id`, A.`unit_sku` FROM (SELECT @UNITRN := @UNITRN + 1 AS ROWNUM, UNIT_DATE, UNIT_ID, UNIT_SKU FROM UNITS ORDER BY UNIT_SKU, UNIT_DATE ASC) A
JOIN (SELECT @TRANSRN := @TRANSRN + 1 AS ROWNUM, TRAN_DATE, TRAN_ID, UNIT_SKU FROM TRANS ORDER BY UNIT_SKU, TRAN_DATE ASC) B
ON A.UNIT_SKU = B.UNIT_SKU
AND A.ROWNUM = B.ROWNUM
ORDER BY A.UNIT_DATE ASC

MySQL: 按特定顺序连接两个表的不同行？

MySQL: Join distinct rows of two tables in a certain order?

mysql

join

distinct