count（1）返回0？ [英] count(1) return 0?
问题描述
大家好
是否可以获得一个count（1）状态，例如：
select count（1）从结果中，夹具= 4916，胜者=远离胜利者组;
如果没有匹配夹具= 4916
则返回0值而不是绝对没有和胜利者=离开？我完全没有结果。
从结果中选择count（1），其中fixture = 4916，wins = home group by winner;
count
-------
（0行）
有什么想法吗？
谢谢
ciao
Zak
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Zak McGregor写道：大家好
是不是可能le得到一个count（1）statemment，例如这里：
从结果中选择count（1），其中fixture = 4916，wins = away group by winner;
to如果没有行匹配fixture = 4916
和winner = away，则返回0值而不是绝对没有值？我完全没有任何结果。
从结果中选择count（1），其中fixture = 4916，wins = home group by winner;
count
------ -
（0行）
有什么想法吗？
不确定我明白你想要什么，但试试像这个：
当count（*）>时选择大小写0然后'''''''''''''''''''''''''''''''''''''''''''
潜在技术
http://www.potentialtech.com
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On Sun，2004年2月29日19:55:15 -0500
Bill Moran< wm **** @ potentialtech.com>写道：
不确定我理解你想要什么，但尝试这样的事情：
当count（*）>时选择案例0然后''''''''''''''''''''''''''''''''''''''''''''''当结果集中没有任何记录
时，我根本就没有行 - 所以在案例中......除了
中的某种表达式，选择本身也可以。
我正在寻找的是一种选择0的方法。如果没有返回任何行，或者从查询返回的行总数为
。
不过感谢你。
Ciao
Zak
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Zak McGregor写道：On Sun，2004年2月29日19:55:15 -0500
Bill Moran< wm ****@potentialtech.com>写道：
不确定我理解你想要什么，但尝试这样的事情：
当count（*）>时选择案例0然后'''''''''''''''''''''''''''''''''''''''''
不幸的是，这不起作用。当结果集中没有任何记录时，我根本就没有行 - 所以在案例中......其他表达式中的选择本身也会有效。
我是什么我正在寻找一种选择0的方法。如果没有返回行，或者从查询返回的总行数。否则。
我怀疑我还是不明白你是什么''尝试这样做，但是......
当count（*）>时选择案例0然后1其他0结束...
我应该建议的。
-
Bill Moran
潜在技术
http：//www.potentialtech .com
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Hi all
is it possible to get a count(1) statemment, for example here:
select count(1) from results where fixture=4916 and winner=away group by winner;
to return a 0 value instead of absolutely nothing if no rows match fixture=4916
and winner=away? I get absolutely no results at all.
select count(1) from results where fixture=4916 and winner=home group by winner;
count
-------
(0 rows)
any ideas please?
Thanks
ciao
Zak
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解决方案Zak McGregor wrote:Hi all
is it possible to get a count(1) statemment, for example here:
select count(1) from results where fixture=4916 and winner=away group by winner;
to return a 0 value instead of absolutely nothing if no rows match fixture=4916
and winner=away? I get absolutely no results at all.
select count(1) from results where fixture=4916 and winner=home group by winner;
count
-------
(0 rows)
any ideas please?
Not really sure I understand what you want, but try something like this:
select case when count(*) > 0 then ''''t'''' else ''''f'''' end from ...
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Bill Moran
Potential Technologies
http://www.potentialtech.com
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On Sun, 29 Feb 2004 19:55:15 -0500
Bill Moran <wm****@potentialtech.com> wrote:
Not really sure I understand what you want, but try something like this:
select case when count(*) > 0 then ''''t'''' else ''''f'''' end from ...
Unfortunately that does not work. When the resultset contains no records
whatsoever, I get no rows at all - so on case...else sort of expression within
the select itself will work.
What I am looking for is a way to select "0" if no rows are returned, or the
total number of rows returned from the query otherwise.
Thanks anyways though.
Ciao
Zak
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Zak McGregor wrote:On Sun, 29 Feb 2004 19:55:15 -0500
Bill Moran <wm****@potentialtech.com> wrote:Not really sure I understand what you want, but try something like this:
select case when count(*) > 0 then ''''t'''' else ''''f'''' end from ...
Unfortunately that does not work. When the resultset contains no records
whatsoever, I get no rows at all - so on case...else sort of expression within
the select itself will work.
What I am looking for is a way to select "0" if no rows are returned, or the
total number of rows returned from the query otherwise.
I suspect that I still don''t understand what you''re trying to do, but ...
select case when count(*) > 0 then 1 else 0 end from ...
Was what I should have suggested.
--
Bill Moran
Potential Technologies
http://www.potentialtech.com
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