sql - How to use Union or Intersect instead of an OR in my Join -


the query below works, i've read, or in join not efficient way results. think maybe should using union or intersect, can't figure out how accomplish that. can explain 'proper' results?

with cte1 (select sc, sn, count(al) unexcused                att                al = 'u'                group sc, sn),      cte2 (select sc, sn, count(al) suspended                att                al = 's'                group sc, sn)  select stu.id, stu.sc, stu.sn,         isnull(cte1.unexcused, '') unx,        isnull(cte2.suspended, '') sus  cte2 full join cte1         on cte1.sc = cte2.sc            , cte1.sn = cte2.sn join stu    on (cte1.sc = stu.sc        , cte1.sn = stu.sn)       or (cte2.sc = stu.sc           , cte2.sn = stu.sn) stu.sc in (1,2,4,9,11,15)

this sample of output:

id      sc  sn     unx  sus 4291432 15  602    0    8 4296250 15  688    6    3 4216462 15  695    0    12 4916602 15  623    0    2 4295193 1   150    1    0 4215874 2   216    1    0 4005707 15  297    1    0

thank you.

personally, i'd change query around this:

with cte1 (select sc, sn, count(al) unexcused                att                al = 'u'                group sc, sn),      cte2 (select sc, sn, count(al) suspended                att                al = 's'                group sc, sn)  select stu.id, stu.sc, stu.sn,         isnull(cte1.unexcused, '') unx,        isnull(cte2.suspended, '') sus  stu left join cte1        on (cte1.sc = stu.sc             , cte1.sn = stu.sn)  left join cte2         on (cte2.sc = stu.sc             , cte2.sn = stu.sn) stu.sc in (1,2,4,9,11,15)

.... if no other reason makes intended results little more clear. note optimizer may still generate same explain plan.


Comments

Post a Comment

Popular posts from this blog

c# - DetailsView in ASP.Net - How to add another column on the side/add a control in each row? -

i have detailsview control on page used edit various fields of record, works in respect. i looking way add 1 column (and if works, why not more) right, absolutely read-only, show same fields of record comparison purposes. i aware there no obvious way such thing out of box detailsview . have looked other controls (transposed gridview , recommended formview , listview ), nothing satisfies. have special data binding setup using detailsview , can't out of without losing features. anyone on how "hack in" additional columns (for display only) on detailsview ? the solution have now, use second detailsview , visible set false in aspx. in code, make sure databind hidden detailsview hosts data third column first, initial detailsview named itemdetails . and in item created event, pass third column html rendering of hidden controls (in last code block) : protected void itemdetails_itemcreated(object sender, eventargs e) { if (dataite
Read more

javascript - firefox memory leak -

i have following script (i use raphaeljs also) draws circle, waits 1 second, draws circle again, etc (you can copy paste - functional, need include raphael raphaeljs.com): <div id="holder"> </div> <script src="raphael.js" type="text/javascript"></script> <script> var paper = raphael(10, 50, 320, 200); var rad = math.pi / 180; var finangle = 0; function sector(cx, cy, r, startangle, endangle, params) { var x1 = cx + r * math.cos(-startangle * rad), x2 = cx + r * math.cos(-endangle * rad), y1 = cy + r * math.sin(-startangle * rad), y2 = cy + r * math.sin(-endangle * rad); return ["m", cx, cy, "l", x1, y1, "a", r, r, 0, +(endangle - startangle > 180), 0, x2, y2]; } var path = sector(100,100,50,0,180); var arc = paper.path(path); function draw() { path = sector(100,100,50,0,finangle);
Read more

Trying to import CSV file to a SQL Server database using asp.net and c# - can't find what I'm missing -

i student , quite new programming, , given task using asp.net , c#, without being taught either. plan learn teach ourselves. the task stuck on making website import csv file sql server database of last year's room bookings around campus. the table has following columns: request_id; priority; module_id; day; start_time; length; park; students; room_code; status; semester_id; linked_request; week_1; week_2; week_3; week_4; week_5; week_6; week_7; week_8; week_9; week_10; week_11; week_12; week_13; week_14; week_15; ) in code, try make work 3 columns (request_id,priority,module) starters. when press import button, want read .csv file (with fixed name @ fixed directory) eg "1,2,3" - comma separating fields [delimiter] - , import sql server datab
Read more