同时通话

Question

我正在尝试通过查看日期时间范围来计算特定呼叫时的同时呼叫数.我的查询有效,但只需要约10分钟即可执行95,000条记录,这太长了.任何优化的想法？

SELECT r.*,
       rr.ChannelsActive  'ChannelsActive'
FROM #rg r
OUTER APPLY
(
      SELECT SUM(1) AS ChannelsActive
      FROM #rg r_inner 
      WHERE 
      (
             r_inner.CallStart BETWEEN r.CallStart AND r.CallEnd 
            OR r_inner.CallEnd BETWEEN r.CallStart AND r.CallEnd
            OR r.CallStart BETWEEN r_inner.CallStart AND r_inner.CallEnd 
            OR r.CallEnd BETWEEN r_inner.CallStart AND r_inner.CallEnd

      )
 ) rr

示例数据

CREATE TABLE #rg
  (
     CallStart DATETIME,
     CallEnd   DATETIME
  )

CREATE INDEX ix1
  ON #rg(CallStart, CallEnd)

CREATE INDEX ix2
  ON #rg(CallEnd, CallStart);

WITH T(N, R)
     AS (SELECT TOP (95000) ROW_NUMBER() OVER (ORDER BY (SELECT 0)) AS RN,
                            ABS(120 + 30 * SQRT(-2 * LOG(ABS(CAST(CAST(CRYPT_GEN_RANDOM(8) AS BIGINT) AS FLOAT) / 9223372036854775807))) * COS(2 * PI() * ABS(CAST(CAST(CRYPT_GEN_RANDOM(8) AS BIGINT) AS FLOAT) / 9223372036854775807)))
         FROM   sys.all_objects o1,
                sys.all_objects o2)
INSERT INTO #rg
SELECT DATEADD(SECOND, N, GETDATE()),
       DATEADD(SECOND, N + R, GETDATE())
FROM   T 

Answer 1

使用这样的 SQL 来获取开始/结束事件的列表...

Select CallStart, 1 As CallCount From #rg
Union All
Select CallEnd, -1 From #rg
Order By CallStart

...然后将其视为一个简单的运行总计问题，根据您的 SQL Server 版本以不同的方式解决该问题，或者如果可以的话可以在代码中轻松解决。