SQL这些是一样的吗？

Question

这些都一样吗？

INNER JOIN dbo.ReportingLevels rl ON e.ei_CompanyID = rl.rl_CompanyId
    AND e.ei_Level = rl.rl_index
    AND EXISTS (SELECT * FROM @ReportingLevelId rlid
                WHERE rlid.[reportLevelName] = rl.[rl_name])    
    AND EXISTS (SELECT * FROM @ReportingLevelId rlid
                WHERE rlid.[companyid] = rl.[rl_CompanyId])

这是第二个.

INNER JOIN dbo.ReportingLevels rl ON e.ei_CompanyID = rl.rl_CompanyId
    AND e.ei_Level = rl.rl_index
    AND EXISTS (SELECT * FROM @ReportingLevelId rlid
                WHERE rlid.[reportLevelName] = rl.[rl_name]
                  AND rlid.[companyid] = rl.[rl_CompanyId]))    

我认为这些是相同的,但是当我使用类似的变体时,我得到了一个奇怪的结果.

Answer 1

不,他们不是.如果表@ReportingLevelId中存在rl_name和rl_CompanyId,则第一个将选择一行,但不一定在同一行中.第二个要求这些值存在于同一行中.