小编ris*_*ism的帖子

我有以下查询，在少于 100K 行的数据集上运行最多需要 2 秒。

我的 SQL 非常生疏，但这看起来像是做的工作比它应该做的多。任何人都可以提供一些关于在哪里寻找加快速度的指示吗？

SELECT
    a.AddressID,
    IsPrincipal = CASE
    WHEN EXISTS(SELECT TOP 1 1 FROM dbo.Setting s WHERE s.SettingValue = a.AddressID AND s.SettingDefinitionID = 3 AND s.ProfileID = 1)
                THEN 1
                ELSE 0
            END,
    IsPickUp = CASE
                WHEN EXISTS(SELECT TOP 1 1 FROM dbo.AddressRole ar WHERE ar.AddressID = a.AddressID AND ar.[AddressRoleTypeID] = 2)
                THEN 1
                ELSE 0
            END,
    IsSender = CASE
                WHEN EXISTS(SELECT TOP 1 1 FROM dbo.AddressRole ar WHERE ar.AddressID = a.AddressID AND ar.[AddressRoleTypeID] = …