sql - Approach to index on Multiple Join columns on same Table? -

-

Many tables have been included in each other and for me to be in a condition for a vertical table There are many columns for.

For example 

  select an a.av, b.qc TableA Add an INNER TableB b ON (a.id = b.id and a.status = '20' and a.flag = 'wrong' and a.num (1,2,4))   
 how approach should be.  
  Include TableA (id, status, flag, number) on non-cloned index N_IX_Test (av); 2. Include the informal index N_IX_Test1 in Table (qc);   
 I could have thought that these are two approaches, all the time when I see a number of columns when I am in position for the same table, I make it as a whole index and Is it OK to add columns to include in the selection list?   
 
 
 Different algorithms require different sequences. Your indexing approach is only good for joining the nested loop, but I think it is a better option to be involved in a hash in that case. However, there is a move that makes an index useful for joining the hash along with nested loop: predicts non-job in the index already:  
  Nonclassed index N_IX_Test ON TableA (Status, Flag, ID, Number) contains (av);   
  num  is still the last one because it does not compare to equality.  
 This is just a wild guess, accurate advice is possible only if you provide more information such as package indexes (if any) and execution plans too.  
 Reference:  
     
  •

Comments

Post a Comment

Popular posts from this blog

php - how to change mysql_result($res, 0, "url"); to mysqli -

-
I do not know how to use mysqli_result like in the past. Is this OK? How is right WHERE status = 'popup' and creditsp> = 1 and (CH) from $ res = mysqli_query ($ con, "SELECT` id`,` usrid`, `url` site Lt; cf || cf = 0) sequence by rand () border 1 "); $ Urll = mysqli_result ($ res, 0, "url"); $ Ownerid = mysqli_result ($ res, 0, "Elixir"); $ Citid = mascile_salt ($ res, 0, "id"); Use fetch_assoc on the results: $ line = $ res-> gt; Fetch_assoc (); $ Urll = $ line ['url']; $ Owner = $ line ['nectar']; $ Site id = $ line ['id']; If there are more than one line, then: while ($ line = $ res-> fetch_assoc ()) {// process $ Line}
Read more

c# - Textbox not clickable but editable -

-
I have a small form with 10 text boxes, I have set them in the correct tab order. I want them on my tab service I was wondering if there is a way to set the text box so that they can be selected for editing until they are tabbed. That is ... I do not want the end user to edit the text box to click on them, I just want to make them editable through tabu. this should do the trick public partial category poor text box: Text Box {Safe Override Zero WndProc (Ref: Message Message) {if (m.msg == (Int) WM.LBUTTONDOWN) {Return; // mount down events} base.WndProc (ref m); }} Window message enum can be found. How to do this without anherizing: text box : class EatMouseDown: netwindows {safe override zero WndProc (ref message message) {if (m.msg == (int) WM.LBUTTONDOWN) {return; } Base.WandProc (Ref M); }} Safe Override Zero Onload (EventEurge E) {base.OnLoad (e); How to do this without any part: left a clean part, whatever is important, this can be a buggy but it works R...
Read more

Matlab transpose a table vector -

-
An embarrassing simple question seems to be, but how can I move a Matlab table vector? aTableT = aTable '; I tried a standard syntax for the simple interaction of a line vector to a line vector aTable : ATableT = reshape (aTable, 1, Height (aTable)); and aTableT = rot90 (aTable); According to the head, the last time table should work for table, see. However, I get this error code: Error type in using table / permit (line 396) Undefined function 'permute' for the input arguments. Error in rot 90 (line 29) b = magnitude (b, [2 1 3: ndims (a)]); NB: fliplr is not useful either pretty sure I have covered clear angles - any ideas? Thanks! Try changing your table into an array, move it, then back to a table In other words, try doing this: aTableArray = table2array (aTable); ATableT = array 2table (aTableArray. '); I have also read the document for rot90 , and it says that rot90 is definitely working for tables Do, and I find you...
Read more