更新查询占用了太多的资源，尽管与存在一起使用，我们可以优化它吗 [英] update query taking too much eventhough used with exists, can we optimize this

问题描述

UPDATE Elig SET EndDate =
(SELECT MAX(CONVERT(char(8),Row_End_Dt,112))
FROM Enrollment
WHERE ID = Mbr_ID AND CovType = 'DD'
AND EffDate BETWEEN Row_Eff_Dt AND Row_End_Dt
AND EndDate > Row_End_Dt)
WHERE EXISTS (SELECT 'X' FROM Enrollment
WHERE ID = Mbr_ID AND CovType = 'DD'
AND EffDate BETWEEN Row_Eff_Dt AND Row_End_Dt
AND EndDate > Row_End_Dt)

推荐答案

SQL Server Management Studio在性能监视中非常有用.否则，您可以查看查询执行计划.

SQL Server Management Studio is pretty useful in Performance Monitoring. Or else, you can review the query execution plan.

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