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我们有以下查询在 MSSQL 中完美运行，但在 MySQL 中运行失败：

select CONVERT(datetime, dateVal) as DateOccurred, itemID, COUNT(*) as Hits from (
select itemID, CONVERT(datetime, DateClickUTC) as dateVal
from tb_items
where DateClickUTC >= '2008-06-03 22:00:28.893' and DateClickUTC <= '2013-06-03 22:00:28.893'
group by CONVERT(datetime, DateClickUTC), UserID, itemID) as a
group by a.dateVal, itemID

我们从 MySQL 得到的错误是：

语法错误，意外 IDENT_QUOTED

此错误发生在第一行的 dateVal 变量上：“Select CONVERT(datetime, dateVal )”。

如果我们删除第一个 CONVERT 错误然后移动到下一行的下一个 CONVERT。因此，显然，我们的日期时间转换似乎存在错误。不知道我们做错了什么，有什么想法吗？谢谢大家。

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1 回答 1

2

我更喜欢使用CAST，但正如其他人所说，您需要在字段之后指定类型，如下所示：

convert(DateClickUTC,datetime)

这是一个使用的工作示例CAST：

select  a.dateVal as DateOccurred, itemID, COUNT(*) as Hits 
from (
  select itemID, cast(DateClickUTC as datetime) as dateVal
  from tb_items
  where DateClickUTC >= '2008-06-03 22:00:28.893' and DateClickUTC <= '2013-06-03 22:00:28.893'
  group by cast(DateClickUTC as datetime), UserID, itemID
) as a
group by a.dateVal, itemID

顺便说一句——在这种情况下，您实际上不需要子查询——这也应该有效：

select cast(DateClickUTC as datetime) as DateOccurred, 
   itemID, 
   COUNT(*) as Hits 
from tb_items
where DateClickUTC >= '2008-06-03 22:00:28.893' and DateClickUTC <= '2013-06-03 22:00:28.893'
group by cast(DateClickUTC as datetime), itemID
于 2013-06-04T22:45:51.593 回答