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我怎样才能允许 1 - 10 秒的容差?

我有 2 个带有时间戳的表,但延迟了 1-10 秒。我正在使用内部连接来比较它们。我在两个表中都有电话号码(列)匹配但不能使它们与时间戳匹配(仅限时间)。为了允许一定的容忍度,我可以使用类似的表达式cast(DateCreated as Time) = cast(TIMESTAMP as time) + 5。但我不想每一秒都这样做。

SELECT Time_To_Sec(cast("table1_DateCreated" as time)) as DateCreated 
     , Time_To_Sec(cast("table2"."Timestamp" as time)) as Timestampe
     , "Direction","FromTW", "ToTW", "table2"."ANI","table2"."CALL ID"
     , "table2"."Disposition"
FROM "calls and time"
INNER JOIN "table2" on cast(DateCreated as Time)=cast(TIMESTAMP as time)+5
                   and FromTW="table2"."ANI"

如果可能的话,我希望看到以下结果:

table1(DateCreated)  |  table2(Timestamp)  | compared results
---------------------+---------------------+-----------------
5000                 |  5005               |  table3
5001                 |  5009               |  table3
5001                 |  5050               |  not in table3   

如果满足条件,则将其发送到表 3,但如果不满足条件,则不会将其发送到表 3。

使用 Zoho 报告,因此我不确定他们使用的是什么类型的数据库。Postgres、MySQL 等

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2 回答 2

4

如果两个表中的时间戳都可以off by 1-10 seconds,那么从逻辑上讲,匹配的最大容差是20 秒(每边 +/- 10)。

Postgres中测试:

SELECT *
FROM   "calls and time" t1
JOIN   table2 t2 ON t2."TIMESTAMP" BETWEEN t1."DateCreated" - interval '20 sec'
                                       AND t1."DateCreated" + interval '20 sec';
WHERE  t1."FromTW" = t2."ANI"  -- FromTW or "FromTW" ?

这是一个sargable表达式,允许在 上使用索引x

x BETWEEN y - interval '20 sec'
      AND y + interval '20 sec'

"calls and time", "TIMESTAMP","FromTW"非常不幸的标识符,顺便说一句。坚持使用合法的、未引用的名称以节省一些麻烦。

于 2015-04-15T19:06:14.123 回答
0

检查两个时间戳的绝对差异,这将是伪代码:

if (abs($timestamp1 - $timestamp2) <= $tolerance) { ... }
于 2015-04-15T18:49:02.410 回答