Unix Technical Forum

return min between 2 fields

This is a discussion on return min between 2 fields within the MySQL forums, part of the Database Server Software category; --> Hi all, I've to return only 1 field with the minimum value coming from 2 tables: select min(table1.datetimex) as ...


Go Back   Unix Technical Forum > Database Server Software > MySQL

FAQ Members List Calendar Search Today's Posts Mark Forums Read
  #1 (permalink)  
Old 02-28-2008, 11:27 AM
Bob Bedford
 
Posts: n/a
Default return min between 2 fields

Hi all,

I've to return only 1 field with the minimum value coming from 2 tables:

select min(table1.datetimex) as mindate1, min(table2.datetimex) as mindate2
from table1 left join table 2 on table1.id = table2.id where table1.id = 123
or table2.id = 123

In fact I've to check the minimum date if a record has been created in
table1 or table2.

I've tried min(table1.datetimex, table2.datetimex) as mindate but it doesn't
work.

How can I do that ?

Also if there is nothing in table1 and something in table2, do I have a
result ?

Thanks for helping

Bob


Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #2 (permalink)  
Old 02-28-2008, 11:27 AM
ZeldorBlat
 
Posts: n/a
Default Re: return min between 2 fields

On Sep 18, 8:12 am, "Bob Bedford" <b...@bedford.com> wrote:
>
> Also if there is nothing in table1 and something in table2, do I have a
> result ?
>


Suppose you have nothing in your left hand and nothing in your right
hand. Which of the two nothings is smaller?

Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #3 (permalink)  
Old 02-28-2008, 11:27 AM
Bob Bedford
 
Posts: n/a
Default Re: return min between 2 fields

>> Also if there is nothing in table1 and something in table2, do I have a
>> result ?
>>

>
> Suppose you have nothing in your left hand and nothing in your right
> hand. Which of the two nothings is smaller?


my question was: nothing in my left and and something in my right hand....in
a query.


Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #4 (permalink)  
Old 02-28-2008, 11:27 AM
Kees Nuyt
 
Posts: n/a
Default Re: return min between 2 fields

On Tue, 18 Sep 2007 14:12:43 +0200, "Bob Bedford"
<bob@bedford.com> wrote:

>Hi all,
>
>I've to return only 1 field with the minimum value coming from 2 tables:
>
>select min(table1.datetimex) as mindate1, min(table2.datetimex) as mindate2
>from table1 left join table 2 on table1.id = table2.id where table1.id = 123
>or table2.id = 123
>
>In fact I've to check the minimum date if a record has been created in
>table1 or table2.
>
>I've tried min(table1.datetimex, table2.datetimex) as mindate but it doesn't
>work.
>
>How can I do that ?
>
>Also if there is nothing in table1 and something in table2, do I have a
>result ?


Perhaps:
SELECT min(datetimeex)
FROM (
SELECT id,datetimexe FROM table1
UNION
SELECT id,datetimexe FROM table2
) WHERE id = 123;

?

>Thanks for helping
>
>Bob

--
( Kees
)
c[_] Truck Pulls: for people who cannot understand the WWF (#371)
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
  #5 (permalink)  
Old 02-28-2008, 11:27 AM
Kees Nuyt
 
Posts: n/a
Default Re: return min between 2 fields

On Wed, 19 Sep 2007 18:20:53 +0200, Kees Nuyt
<k.nuyt@nospam.demon.nl> wrote:

>On Tue, 18 Sep 2007 14:12:43 +0200, "Bob Bedford"
><bob@bedford.com> wrote:
>
>>Hi all,
>>
>>I've to return only 1 field with the minimum value coming from 2 tables:
>>
>>select min(table1.datetimex) as mindate1, min(table2.datetimex) as mindate2
>>from table1 left join table 2 on table1.id = table2.id where table1.id = 123
>>or table2.id = 123
>>
>>In fact I've to check the minimum date if a record has been created in
>>table1 or table2.
>>
>>I've tried min(table1.datetimex, table2.datetimex) as mindate but it doesn't
>>work.
>>
>>How can I do that ?
>>
>>Also if there is nothing in table1 and something in table2, do I have a
>>result ?

>
>Perhaps:
>SELECT min(datetimeex)
> FROM (
> SELECT id,datetimexe FROM table1
> UNION
> SELECT id,datetimexe FROM table2
>) WHERE id = 123;
>
>?


Or (probably more efficient):
SELECT min(datetimeex)
FROM (
SELECT id,datetimexe FROM table1 WHERE id = 123
UNION
SELECT id,datetimexe FROM table2 WHERE id = 123
);


>>Thanks for helping
>>
>>Bob

--
( Kees
)
c[_] Truck Pulls: for people who cannot understand the WWF (#371)
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On
Forum Jump


All times are GMT. The time now is 03:02 PM.


Powered by vBulletin® Version 3.6.5
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.2.0
www.UnixAdminTalk.com