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 ...
| |||||||
| FAQ | Members List | Calendar | Search | Today's Posts | Mark Forums Read |
| ||||
| 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 |
| |||
| 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? |
| |||
| >> 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. |
| |||
| 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) |
| ||||
| 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) |