问题描述
为什么COALESCE(date1,date2)
返回Blob
(二进制)?两列都是DATETIME
类型.
Why does COALESCE(date1,date2)
return Blob
(binary)? Both columns are of type DATETIME
.
这是完整的sql查询:
Here's the complete sql query:
SELECT COALESCE( last_modified, date_purchased )As LastModifiedOrPurchased
FROM Orders
ORDER BY COALESCE( last_modified, date_purchased )DESC
LIMIT 1;
我通常使用SQL Server作为rdbms,但是需要编写一个同步工具.现在,我正在尝试选择两个日期之一.如果last_modified
为空,则应返回date_purchased
.
I'm normally using SQL-Server as rdbms but need to write a synchronization tool. Now i'm trying to select one of two dates. If last_modified
is null date_purchased
should be returned.
但是,即使有多个记录的两个日期都不为空,查询也只返回Blob
.如何获得正确的最后日期?
But even if there are multiple records where both dates are not null, the query returns just Blob
. How to get the correct last date?
编辑:在 SQL-Fiddle 上strong> 不能用MySql 5.1.61(我在5.0.51上)重现.
Edit: on SQL-Fiddle it is not reproducable with MySql 5.1.61 (i'm on 5.0.51).
推荐答案
这可能是已修复的错误: 错误35662
This is probably a bug that has been fixed: bug-35662
说明:
COALESCE(date, date)
在Windows的 5.0.51a上返回varbinary XP 32位(仅测试了这种口味)
Description:
COALESCE(date, date)
returns varbinary on 5.0.51a for Windows XP 32bit (only tested this flavor)
COALESCE(date,date)
在Mac OS上返回日期
COALESCE(date,date)
returns date on Mac OS
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[2008年3月31日17:41] Omer BarNir
该错误已在5.0.52中修复,在测试5.0.56-关闭时未观察到
[31 Mar 2008 17:41] Omer BarNir
The bug was fixed in 5.0.52 and was not observed when testing 5.0.56 - closing
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