union function differenct between sql server 2005 and 2008?# Database - 数据库
l*y
1 楼
http://www.tudou.com/programs/view/RafvGpkPykc/
嗓音真不错啊
高旗应该把这歌录一下
嗓音真不错啊
高旗应该把这歌录一下
i*7
2 楼
有这样一个table A
ReportYear, ReportMonth, Reportdate, and others
以前用sql server 2005, 用以下query
Select year,month,date, other from A
Where criteria 1
Union
Select year,month,date, other from A
Where criteria 2
Query result自动按照年，月，日的顺序排列。
现在用sql server 2008,一样的query 得出的结果不是按照年，月，日由小到大的顺序
排列了。日期在后面可能排在前，这是为什么？
谢谢！
ReportYear, ReportMonth, Reportdate, and others
以前用sql server 2005, 用以下query
Select year,month,date, other from A
Where criteria 1
Union
Select year,month,date, other from A
Where criteria 2
Query result自动按照年，月，日的顺序排列。
现在用sql server 2008,一样的query 得出的结果不是按照年，月，日由小到大的顺序
排列了。日期在后面可能排在前，这是为什么？
谢谢！
B*g
3 楼
algorithm changed.
same thing happened for oracle 9i to oracle 10g.
If you need order, add order by
【在 i******7 的大作中提到】
: 有这样一个table A
: ReportYear, ReportMonth, Reportdate, and others
: 以前用sql server 2005, 用以下query
: Select year,month,date, other from A
: Where criteria 1
: Union
: Select year,month,date, other from A
: Where criteria 2
: Query result自动按照年，月，日的顺序排列。
: 现在用sql server 2008,一样的query 得出的结果不是按照年，月，日由小到大的顺序
same thing happened for oracle 9i to oracle 10g.
If you need order, add order by
【在 i******7 的大作中提到】
: 有这样一个table A
: ReportYear, ReportMonth, Reportdate, and others
: 以前用sql server 2005, 用以下query
: Select year,month,date, other from A
: Where criteria 1
: Union
: Select year,month,date, other from A
: Where criteria 2
: Query result自动按照年，月，日的顺序排列。
: 现在用sql server 2008,一样的query 得出的结果不是按照年，月，日由小到大的顺序
i*a
4 楼
Select year,month,date, other from A
Where criteria = 1
or criteria = 2
order by criteria, year, month, date
【在 i******7 的大作中提到】
: 有这样一个table A
: ReportYear, ReportMonth, Reportdate, and others
: 以前用sql server 2005, 用以下query
: Select year,month,date, other from A
: Where criteria 1
: Union
: Select year,month,date, other from A
: Where criteria 2
: Query result自动按照年，月，日的顺序排列。
: 现在用sql server 2008,一样的query 得出的结果不是按照年，月，日由小到大的顺序
Where criteria = 1
or criteria = 2
order by criteria, year, month, date
【在 i******7 的大作中提到】
: 有这样一个table A
: ReportYear, ReportMonth, Reportdate, and others
: 以前用sql server 2005, 用以下query
: Select year,month,date, other from A
: Where criteria 1
: Union
: Select year,month,date, other from A
: Where criteria 2
: Query result自动按照年，月，日的顺序排列。
: 现在用sql server 2008,一样的query 得出的结果不是按照年，月，日由小到大的顺序
i*a
5 楼
is that the cause, or is it because the records' physical order changed
when migrating the database from 2005 to 2008?
【在 B*****g 的大作中提到】
: algorithm changed.
: same thing happened for oracle 9i to oracle 10g.
: If you need order, add order by
when migrating the database from 2005 to 2008?
【在 B*****g 的大作中提到】
: algorithm changed.
: same thing happened for oracle 9i to oracle 10g.
: If you need order, add order by
p*d
6 楼
Is this the case, Beijing? Definitely if the physical order changed the
query result set order will change too if no ORDER BY clause specified.
【在 i****a 的大作中提到】
: is that the cause, or is it because the records' physical order changed
: when migrating the database from 2005 to 2008?
query result set order will change too if no ORDER BY clause specified.
【在 i****a 的大作中提到】
: is that the cause, or is it because the records' physical order changed
: when migrating the database from 2005 to 2008?
h*l
7 楼
This one is NOT the same as the union query.
Union removes duplicates.
【在 i****a 的大作中提到】
: Select year,month,date, other from A
: Where criteria = 1
: or criteria = 2
: order by criteria, year, month, date
Union removes duplicates.
【在 i****a 的大作中提到】
: Select year,month,date, other from A
: Where criteria = 1
: or criteria = 2
: order by criteria, year, month, date
i*a
8 楼
good catch
then:
Select year,month,date, other from A
Where criteria 1
Union
Select year,month,date, other from A
Where criteria 2
order by year, month, date
【在 h**l 的大作中提到】
: This one is NOT the same as the union query.
: Union removes duplicates.
then:
Select year,month,date, other from A
Where criteria 1
Union
Select year,month,date, other from A
Where criteria 2
order by year, month, date
【在 h**l 的大作中提到】
: This one is NOT the same as the union query.
: Union removes duplicates.
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