Question

我想做这样的BOLD部分。我不知道是否有可能。请帮帮我。之间的部分 //开始和//结束有可能吗？

SELECT a.id, b.id, b.number, c.total,

//Start

SUM(total WHERE c.id=a.id) AS sum_total

//End

FROM table_1 a
LEFT JOIN table_2 b ON a.id=b.id
INNER JOIN table_4 ON b.company=c.company
INNER JOIN table_3 c ON b.number=c.id_number
WHERE b.date BETWEEN 'date_1' AND 'date_2'
ORDER BY d.company ASC

Answer 1

当然有可能。请尝试以下SQL：

SELECT a.id, b.id, b.number, SUM(c.total)TOTAL,

//Start

SUM(case when c.id=a.id then total else 0 end) AS sum_total

//End

FROM table_1 a
LEFT JOIN table_2 b ON a.id=b.id
INNER JOIN table_4 ON b.company=c.company
INNER JOIN table_3 c ON b.number=c.id_number
WHERE b.date BETWEEN 'date_1' AND 'date_2'
GROUP BY 1,2,3
ORDER BY d.company ASC

Answer 2

您使用GROUP BY来执行此操作，类似于：

SELECT a.id, b.id, b.number, c.total,

//Start

SUM(total) AS sum_total

//End

FROM table_1 a

LEFT JOIN table_2 b ON a.id=b.id
INNER JOIN table_4 ON b.company=c.company
INNER JOIN table_3 c ON b.number=c.id_number
WHERE b.date BETWEEN 'date_1' AND 'date_2' AND
      c.id = a.id
GROUP BY a.id, b.id

ORDER BY d.company ASC

http://www.w3resource.com/sql/aggregate-functions/sum-with-group-by.php

查询动态操作

2 个答案: