WHERE子句使用临时列的SQL Server
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19-09-2019 - |
题
我有以下查询,其使用CASE语句。 反正是有添加到WHERE子句WHERE IsBusinessDayFinal = 0?不使用临时表?
非常感谢!
SELECT
ac.DateTimeValue,
CASE
WHEN pc.IsBusinessDay IS NOT NULL THEN pc.IsBusinessDay
ELSE ac.IsBusinessDay
END AS IsBusinessDayFinal,
ac.FullYear,
ac.MonthValue,
ac.DayOfMonth,
ac.DayOfWeek,
ac.Week
FROM
[dbo].[AdminCalendar] ac LEFT JOIN
[dbo].ProjectCalendar pc ON ac.DateTimeValue = pc.DateTimeValue AND pc.ProjectId = @projectId
WHERE ac.DateTimeValue >= @startDate AND ac.DateTimeValue <= @finishDate;
解决方案
使用
WHERE (pc.IsBusinessDay IS NULL AND ac.IsBusinessDay = 0)
OR pc.IsBusinessDay = 0
其他提示
WHERE ac.DateTimeValue >= @startDate AND ac.DateTimeValue <= @finishDate
AND ((pc.IsBusinessDay IS NOT NULL AND pc.IsBusinessDay = 0) OR ac.IsBusinessDay = 0)
可以使用 COALESCE 代替CASE,因为你检查空:
SELECT ac.DateTimeValue,
COALESCE(pc.IsBusinessDay, ac.IsBusinessDay) AS IsBusinessDayFinal,
ac.FullYear,
ac.MonthValue,
ac.DayOfMonth,
ac.DayOfWeek,
ac.Week
FROM [dbo].[AdminCalendar] ac
LEFT JOIN [dbo].ProjectCalendar pc ON ac.DateTimeValue = pc.DateTimeValue
AND pc.ProjectId = @projectId
WHERE ac.DateTimeValue >= @startDate
AND ac.DateTimeValue <= @finishDate
AND COALESCE(pc.IsBusinessDay, ac.IsBusinessDay) = 0
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