sql - What is the difference between these two queries pls? -


when updating table or performing query involves comparing 2 tables, have habit of querying below

update dbo.table1 set col = (  select i.colid      dbo.table2        i.did = dbo.table1.did ,           i.[pdate] = dbo.table1.pdate ,          i.pamount = dbo.table1.pay ,           i.[ref no ] = dbo.table1.refno ,          i.[cno ] = dbo.table1.receipt )

and above failed me. returns error saying query returns morethan 1 record/row. superior queried below , works . still cant figure out why mine failed , succeed. , why never failed me before ?

update dbo.table1 set col = i.colid   dbo.table2     i.did = dbo.table1.did ,           i.[pdate] = dbo.table1.pdate ,          i.pamount = dbo.table1.pay ,           i.[ref no ] = dbo.table1.refno ,          i.[cno ] = dbo.table1.receipt

your query fails because returns more 1 row. is, there 2 or more rows match conditions. think pretty obvious error. have scalar subquery. should return @ 1 row , 1 column.

the second works, because joins allowed have multiple rows matching. however, 1 of values set set -- 1 of arbitrary matching rows. in opinion, bad form have multiple multiple matching rows match , have arbitrary value chosen. but, work.


Comments

Post a Comment

Popular posts from this blog

php - Submit Form Data without Reloading page -

i know question has been asked , answered bunch of times life of me can not solution work on code. believe if redo code, work properly, , in retrospect time i've spent on issue should have redone code...but beyond deadline , have working prototype up... can advise how update multiple forms on single page without reloading page? horrible @ php , complete noob js/jquery/ajax @ best. html/php in single file , believe causing me problems/is largest obstacle @ getting ajax form processing work. basically, want users to: select teams multiple dropdowns in form group 1 (league champs) , on update update db newly selected team without reloadding page. edit team scores per match , on score submit/update, update db new scores. for each requirement there multiple forms (1 each leagues, 1 each per match) have set class on each form id. everything works via php, form submission reloads page each time submitted , not ideal. i have tried ajax code here http://scotch.io/tutoria
Read more

linux - Rails running on virtual machine in Windows -

the reason why want switch ubuntu people said gems works better on linux on windows. i don't want macbook pro rails development since love windows , cannot stand lack of apps mac. moreover, people saying ubuntu "better" mac: http://www.reddit.com/r/ubuntu/comments/1bgj1s/are_there_advantages_of_ubuntu_over_os_x_for/ does virtual box work enough doesn't have lag @ all? using i7-3517u cpu 8gb memory. need program in environment lag-free , not sluggish. or there alternatives recommend? i unsure permission settings or complicated stuffs regarding terminal. i'll using terminal develop. i'm still quite new here development in linux. please kind me >< thanks. @holyxiaoxin pretty sure should asking on superuser instead. nevertheless, suggest install ubuntu in partition instead of running virtual machine. here's guide https://help.ubuntu.com/community/windowsdualboot also, yes. developing in virtual machine accurate, @ end experiment w
Read more

php - $params->set Array between square bracket -

i'm using k2 in joomla 3.3. i'm trying set params (items ids ) module k2_content item.php file. result must between brackets, like: ["96","68"] my code is: $query = "select * #__k2_items extra_fields_search = '$myautor' , catid !=1 " ; $db->setquery($query); $losautores = $db->loadobjectlist(); $result = array(); foreach ($losautores $key => $value) { $result[] = '" '.$value->id.' "'; } $string_version = implode(',', $result); $autoresfinal = '['.$string_version.']'; if test using print, looks ok. passing var pramas, 1064 error. $params->set('items', $autoresfinal); to test tried $autoresfinal = ["96","68"]; and works fine. idea why doesn't work? thank you. if assign ["x","y"] assigning an array . here transforming array in st
Read more