Question

我需要从dbo.transaction（所有用户的事务 - 每个用户的多个事务）检索记录，这些记录的时间戳最接近dbo.bal中的时间（每个用户的当前余额详细信息仅一个记录每个用户）

即，结果记录应该等于dbo.bal中记录的数量

这里我尝试了以下查询，我只获得的记录少于dbo.bal中的时间。但是有一些记录的时间戳大于和最接近dbo.bal.time

SELECT dbo.bal.uid,
       dbo.bal.userId,
       dbo.bal.balance,
       dbo.bal.time,
  (SELECT TOP 1 transactionBal
   FROM dbo.transaction
   WHERE TIMESTAMP <= dbo.bal.time
   ORDER BY TIMESTAMP DESC) AS newBal
FROM dbo.bal
WHERE dbo.bal.time IS NOT NULL
ORDER BY dbo.bal.time DESC

这是我的表结构，

dbo.transaction
---------------

| uid| userId   | description| timestamp               | credit | transactionBal
-------------------------------------------------------------------------
| 1  | 101      | buy credit1| 2012-01-25 03:23:31.624 | 100    | 500
| 2  | 102      | buy credit5| 2012-01-18 03:13:12.657 | 500    | 700
| 3  | 103      | buy credit3| 2012-01-15 02:16:34.667 | 300    | 300
| 4  | 101      | buy credit2| 2012-01-13 05:34:45.637 | 200    | 300
| 5  | 101      | buy credit1| 2012-01-12 07:45:21.457 | 100    | 100
| 6  | 102      | buy credit2| 2012-01-01 08:18:34.677 | 200    | 200

dbo.bal
-------

| uid| userId   | balance | time                    |
-----------------------------------------------------
| 1  | 101      | 500     | 2012-01-13 05:34:45.645 |
| 2  | 102      | 700     | 2012-01-01 08:18:34.685 |
| 3  | 103      | 300     | 2012-01-15 02:16:34.672 |

结果应该是，

| Id | userId   | balance | time                    | credit | transactionBal 
-----------------------------------------------------------------------------
| 1  | 101      | 500     | 2012-01-13 05:34:45.645 | 200    | 300
| 2  | 102      | 700     | 2012-01-01 08:18:34.685 | 200    | 200
| 3  | 103      | 300     | 2012-01-15 02:16:34.672 | 300    | 300

请帮助我..任何帮助都必须得到赞赏...谢谢你

Answer 1

如果您发布了表结构，那将会很有帮助，但是......

我认为你的内部查询需要一个连接条件。（这实际上不在您的问题中）
内部查询中的ORDER BY子句可以是ABS(TIMESTAMP - DB0.BAL.TIME)。这应该给你2之间的最小差异。

这有帮助吗？

基于下面的Sql Fiddle http://sqlfiddle.com/#!3/7a900/15，我提出了......

SELECT 
  bal.uid, 
  bal.userId, 
  bal.balance, 
  bal.time,
  trn.timestamp,
  trn.description,
  datediff(ms, bal.time, trn.timestamp)
FROM 
  money_balances bal
  JOIN money_transaction trn on
    trn.userid = bal.userid and
    trn.uid =
    (
      select top 1 uid
      from money_transaction trn2
      where trn2.userid = trn.userid
      order by abs(datediff(ms, bal.time, trn2.timestamp))
    )
WHERE 
  bal.time IS NOT NULL
ORDER BY 
  bal.time DESC

我无法保证其性能，因为我对您的数据一无所知，但我相信它有效。

我简化了我的答案 - 我相信你需要的是

SELECT 
  bal.uid as baluid,   
  (
      select top 1 uid 
      from money_transaction trn2
      where trn2.userid = bal.userid
      order by abs(datediff(ms, bal.time, trn2.timestamp))
  ) as tranuid
FROM 
  money_balances bal

从中您可以获得所需的所有数据集。例如：

with matched_credits as
(
SELECT 
  bal.uid as baluid,   
  (
      select top 1 uid 
      from money_transaction trn2
      where trn2.userid = bal.userid
      order by abs(datediff(ms, bal.time, trn2.timestamp))
  ) as tranuid
FROM 
  money_balances bal 
)
select 
  *
from 
  matched_credits mc
  join money_balances mb on
    mb.uid = mc.baluid
  join money_transaction trn on
    trn.uid = mc.tranuid

Answer 2

尝试：

SELECT dbo.bal.uid,
       dbo.bal.userId,
       dbo.bal.balance,
       dbo.bal.time,
  (SELECT TOP 1 transactionBal
   FROM dbo.transaction
   ORDER BY abs(datediff(ms, dbo.bal.time, TIMESTAMP))) AS newBal
FROM dbo.bal
WHERE dbo.bal.time IS NOT NULL
ORDER BY dbo.bal.time DESC

基于最近时间戳加入两个表的SQL查询

2 个答案: