Question

在下表中，我需要更新列brake_pad，如下所示：

Table ct_maint(simplified). 
Primary key is the combined model_id/fuel columns.

model_id    fuel    brake_pad
   1        gas         0
   1        diesel      0
   2        gas         0
   3        diesel      0
   4        gas         0
   4        diesel      0
   5        diesel      0
   6        gas         0
   6        diesel      0  
   ......

告诉我要更新哪个brake_pad的查询是：

SELECT models.model_id, motors.fuel FROM models
INNER JOIN versions USING(model_id)
INNER JOIN versiontrim USING(version_id)
INNER JOIN motors USING(motor_id)
WHERE trim_id IN(502, 506)
GROUP BY model_id, fuel

此查询提供如下结果集：

model_id      fuel
   1          diesel
   3          diesel
   4          gas
   4          diesel
   6          gas

所以，我想，

UPDATE ct_maint SET brake_pad=1000 WHERE model_id AND fuel IN( SELECT.....)

但是在mysql嗡嗡我之前很久就停止了。

感谢任何帮助。

Answer 1

尝试此查询：

UPDATE ct_maint SET brake_pad=1000 WHERE (model_id, fuel) IN ( SELECT.....)

Answer 2

您可以选择使用两种方法：

1）我认为你可以使用元组IN：

UPDATE ct_maint SET brake_pad=1000 
WHERE (model_id, fuel) IN 
   (SELECT models.model_id, motors.fuel FROM models WHERE ... );

2）您可以在更新中使用联接

UPDATE ct_maint SET brake_pad=1000 
INNER JOIN (SELECT ...) models_upd
ON ct_maint.model_id = models_upd.model_id
AND ct_maint.fuel = models_upd.fuel;

mysql更新，where子句子查询中有2列

2 个答案: