简单谈谈MySQL数据透视表

我有一张这样的产品零件表：

部分

part_id   part_type   product_id--------------------------------------1      A       12      B       13      A       24      B       25      A       36      B       3

product_id   part_A_id   part_B_id----------------------------------------1        1       22        3       43        5       6

最佳答案

不幸的是,MySQL没有PIVOT功能,但您可以使用聚合函数和CASE语句对其进行建模.对于动态版本,您需要使用预准备语句：

SET @sql = NULL;SELECT GROUP_CONCAT(DISTINCT  CONCAT(   'max(case when part_type = ''',part_type,''' then part_id end) AS part_','_id'  ) ) INTO @sqlFROM parts;SET @sql = CONCAT('SELECT product_id,',@sql,'          FROM parts           GROUP BY product_id');PREPARE stmt FROM @sql;EXECUTE stmt;DEALLOCATE PREPARE stmt;

select product_id,max(case when part_type ='A' then part_id end) as Part_A_Id,max(case when part_type ='B' then part_id end) as Part_B_Idfrom partsgroup by product_id

总结

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