mysql - 如何按列显示结果？

Question

我有一些类似的疑问。并希望按列获取结果。是否可以？我什么办法？这是“UNION”的正确语法吗？

示例:

select(
(select total, amount FROM table_1 where sale_type = "type_1" GROUP BY 
total WITH ROLLUP),
(select total, amount FROM table_1 where sale_type = "type_2" GROUP BY 
total WITH ROLLUP),
(select total, amount FROM table_1 where sale_type = "type_3" GROUP BY 
total WITH ROLLUP),
(select total, amount FROM table_1 where sale_type = 
"type_4" GROUP BY 
total WITH ROLLUP),ORDER BY total);

谢谢!

结果表:

 total    type_1     type_2   type_3   type_4
  ...      ...        ...      ...      ...

Answer 1

这个答案是推测性的，因为您没有向我们展示任何示例数据，但我可能建议您需要基于 sale_type 的条件总和。如果是这样，那么以下查询应该符合您的要求:

SELECT
    total,
    SUM(CASE WHEN sale_type = 'type_1' THEN amount ELSE 0 END) AS sum_1,
    SUM(CASE WHEN sale_type = 'type_2' THEN amount ELSE 0 END) AS sum_2,
    SUM(CASE WHEN sale_type = 'type_3' THEN amount ELSE 0 END) AS sum_3,
    SUM(CASE WHEN sale_type = 'type_4' THEN amount ELSE 0 END) AS sum_4
FROM table_1
GROUP BY total WITH ROLLUP;