Question

在这种情况下，我有很多关系问题

表：customer_master

+---------+-----------+
| cust_id | cust_code |
+---------+-----------+
|       1 | S00333    |
+---------+-----------+

表：customer_supply_chain

+----------------+-----------+-------------------+
| supply_cust_id | cust_code | supplye_cust_code |
+----------------+-----------+-------------------+
|              1 | S00333    | HI00001           |
|              2 | S00333    | MA00010           |
+----------------+-----------+-------------------+

表：customer_vehicle

+----------------+-----------+------------------+
| cust_vehicl_id | cust_code | vehicle_model_id |
+----------------+-----------+------------------+
|              1 | S00333    |              161 |
|              2 | S00333    |              162 |
+----------------+-----------+------------------+

Mysql查询是：

SELECT
  cv.vehicle_model_id,
  csc.supply_cust_code AS suppl_code
FROM customer_master cm
  LEFT JOIN customer_supply_chain csc
    ON csc.cust_code = cm.cust_code
  LEFT JOIN customer_vehicle cv
    ON cv.cust_code = cm.cust_code
WHERE cm.cust_code = 'S00333'

查询结果

+------------------+------------------+
| vehicle_model_id | supply_cust_code |
+------------------+------------------+
|              161 | HI00001          |
|              162 | HI00001          |
|              161 | MA00010          |
|              162 | MA00010          | 
+------------------+------------------+

我们的愿望输出是

+------------------+------------------+
| vehicle_model_id | supply_cust_code |
+------------------+------------------+
|              161 | HI00001          |
|              162 | MA00010          |
+------------------+------------------+

supply_cust_code和vehicle_model_id，

重复出现问题

我们尝试使用distinct和group by以及其他修复程序（在堆栈溢出中显示）但不能正常工作，

如果我们使用group by，那么我们无法获取所有数据而我们不想使用group_concat，我们无法解决问题，我们只是尝试获得所有行但不重复

Answer 1

我认为你需要这样的东西：

SELECT
  cv.vehicle_model_id,
  csc.supply_cust_code AS suppl_code
FROM (
    SELECT supply_cust_code, @i := @i + 1 AS pos
    FROM (
      SELECT csc.supply_cust_code
      FROM customer_supply_chain csc
      WHERE csc.cust_code = 'S00333') t,
      (select @i := 0) r ) csc
  LEFT JOIN (
    SELECT vehicle_model_id, @j := @j + 1 AS pos
    FROM (
      SELECT cv.vehicle_model_id
      FROM customer_vehicle cv
      WHERE cv.cust_code = 'S00333') t,
      (select @j := 0) r ) cv ON cv.pos = csc.pos

但是在你确切地说明你需要什么之前，你不可能在这里获得帮助。

Answer 2

我不知道您为什么会收到这些重复项，因为示例数据不支持它，但您可以尝试使用SELECT DISTINCT：

SELECT DISTINCT cv.vehicle_model_id,
                csc.supply_cust_code AS suppl_code
FROM ...

或者您可以尝试对模型ID进行分组并提供客户代码：

SELECT cv.vehicle_model_id,
       csc.supply_cust_code AS suppl_code
FROM customer_master cm
LEFT JOIN customer_supply_chain csc
    ON csc.cust_code = cm.cust_code
LEFT JOIN customer_vehicle cv
    ON cv.cust_code = cm.cust_code
WHERE cm.cust_code = 'S00333'
GROUP BY cv.vehicle_model_id,
         csc.supply_cust_code

在多对多关系mysql中重复行

2 个答案: