需要增强过滤器的 MYSQL 数据透视表

Question

我将 pe_date、pe_batch 和 pe_tarive 列中的值转置到新列 c1、c2 和 c3 中。效果很好。但现在我想从 pe_date 过滤 Date1 和 Date 2 之间的日期值。

在哪里放置 WHERE BETWEEN Date1 和 Date2 语句？想不通。感谢您的帮助！

SELECT t.submit_time,
 (SELECT field_value FROM mytable WHERE submit_time = t.submit_time AND field_name ='pe_date') as 'c1',
 (SELECT field_value FROM mytable WHERE submit_time = t.submit_time AND field_name ='pe_batch') as 'c2',
 (SELECT field_value FROM mytable WHERE submit_time = t.submit_time AND field_name ='pe_tarive') as 'c3'
FROM  mytable
GROUP BY t.submit_time
ORDER BY c1 ASC

Answer 1

我将使用旋转逻辑将其编写为：

SELECT
    submit_time,
    MAX(CASE WHEN field_name = 'pe_date'   THEN field_value END) AS c1,
    MAX(CASE WHEN field_name = 'pe_batch'  THEN field_value END) AS c2,
    MAX(CASE WHEN field_name = 'pe_tarive' THEN field_value END) AS c3
FROM mytable
WHERE
    -- some restriction on the date
GROUP BY
    submit_time;

据我所知，也许您只需要添加一个WHERE 子句。唯一可能对日期进行限制的地方是HAVING 子句。