Question

我有一个mysql表，交易，有字段id，transactionType，数量，价格等。我想通过一列的累积总和来限制记录。所以我想拉出所有交易，直到累积数量达到我的变量（此处＆lt; = 50）。

我做错了什么？

SET @qsum := 0; 
SELECT * 
FROM (
  SELECT *, (@qsum := @qsum + quantity) AS cumulative_quantity 
  FROM transactions ORDER BY id DESC
) transactions 
WHERE 
transactionType = 'buy'
AND typeID = 10
AND cumulative_quantity <= 50

Answer 1

试试这种方式

SET @qsum := 0; 
SELECT * 
FROM (
  SELECT *, (@qsum := @qsum + quantity) AS cumulative_quantity 
  FROM transactions
  WHERE transactionType = 'buy'
   AND typeID = 10
   AND cumulative_quantity <= 50
  ORDER BY id DESC
) transaction

通过值的总和限制查询

1 个答案: