同时通话

我试图通过查看日期时间范围来计算进行特定呼叫时同时呼叫的数量。我的查询有效，但只需要大约 10 分钟才能执行 95,000 条记录，这太长了。有什么优化的想法吗？

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 

这应该可以做到：

 ;WITH cteCallEvents As
 (
        SELECT *, CallStart As EventTime, 1 As EventType FROM #rg r
    UNION ALL
        SELECT *, CallEnd   As EventTime, 0 As EventType FROM #rg r
 )
 , cteCallCounts As
 (
    SELECT *,
        ROW_NUMBER() OVER(Order By EventTime) as EventCount,
        ROW_NUMBER() OVER(Partition By EventType Order By EventTime) as TypeCount
    FROM cteCallEvents
 )
 SELECT *,
    2*TypeCount - EventCount  As OpenCalls
FROM    cteCallCounts
WHERE   EventType = 1

最多需要几秒钟。应该适用于任何 SQL Server 2005+。