比较where子句中的两个日期

Question

我在Where子句上遇到错误＆＃34; X＆＃34;执行此查询时

select top 100 DATEADD(HOUR,10, DateCreated) as X
from y
where X between '2015 -03-31 ' and '2015 -04 -02' 
order by DateCreated desc

Answer 1

查询处理阶段的逻辑顺序是：

1. FROM
2. WHERE
3. GROUP BY
4. HAVING
5. 选择
6. ORDER BY

正如您所见，SELECT之后发生了WHERE。因此，您不能在SELECT子句中使用WHERE部分的任何别名。您只能使用ORDER BY中的别名。

您的查询应该是这样的：

SELECT TOP 100 DATEADD(HOUR, 10, DateCreated) AS X
FROM y
WHERE DATEADD(HOUR, 10, DateCreated) BETWEEN '2015-03-31' AND '2015-04-02' 
ORDER BY DateCreated DESC

我还建议您使用

WHERE DATEADD(HOUR, 10, DateCreated) >= '2015-03-31'
AND DATEADD(HOUR, 10, DateCreated) <= '2015-04-02'

LOGICAL QUERY PROCESSING

What do BETWEEN and the devil have in common?

Answer 2

X是列的别名，因此不能直接在where子句中使用它。

select top 100 DATEADD(HOUR,10, DateCreated) as X
from Table_1
where DATEADD(HOUR,10, DateCreated) between '2015 -03-31 ' and '2015 -04 -02' 
order by DateCreated desc