sql - distinct on 4 billion records -

-

in teradata consider scenario have more 4 billion records in table , need execute distinct/group on column not part of primary or secondary index , not partitioned.

now taking time. there other way of achieving this.

this standalone environment , can not copy data , neither have access create new table in environment. select access have.

if need number of unique values column help statistics {database}.{tablename} provide columns statistics , number of unique values. in teradata 14 or later, can perform show statistics values column {column} on {database}.{tablename}; command provide more details histograms including biased values column. biased values may encompass of unique values column or first few hundred. permissions on table may or may not permit this.

if using statistics out of question because don't exist or don't have sufficient permissions going end scanning table. having statistics collected on column information result in full table scan.

finally, depending on table , column investigating may find data dictionary maintained data modeler(s) have expected domain column. may have completed data profiling against table obtain information.


Comments

Post a Comment

Popular posts from this blog

matlab - "Contour not rendered for non-finite ZData" -

-
i'm trying plot frequency characteristic equation using ezplot, matlab gives following warning, "contour not rendered non-finite zdata". have used command plot frequency equations warning , plot display empty , not change axis range well. can please help. appreciated. here's code i'm using. % transfer matrix case-i, thin rotor clear all; clc; ei = 1626; l = 0.15; m = 0.44108; = 2.178*10^-4; i_p = 2.205*10^-5; itr = 0.24; i_pr = 0.479; syms p n; f = [1 l*1i l^2/(2*ei)*1i l^3/(6*ei); 0 1 l/ei -l^2/(2*ei)*1i; 0 0 1 -l*1i; 0 0 0 l]; p = [ 1 0 0 0; 0 1 0 0; 0 -it*p^2+i_p*n*p 1 0; -m*p^2 0 0 1]; p_r = [1 0 0 0; 0 1 0 0; 0 -itr*p^2+i_pr*n*p 1 0; -m*p^2 0 0 1]; = f*p*f*p*f*p*f; b = p_r*f*p*f*p*f; r = a(1,2)/a(1,4); a12_p = 0; a22_p = a(2,2)-r*a(2,4); a32_p = a(3,2)-r*a(3,4); a42_p = a(4,2)-r*a(4,4); ap(2,2) = a22_p; ap(3,2) = a32_p; ap(4,2) = a42_p; ap(4,4) = 1; c = b*ap; m = [c(3,2) c(3,4); c(4,2) c(4,...
Read more

delphi - Indy UDP Read Contents of Adata -

-
i using indy udp server read string of data. however, not know how work adata parameter. can around converting binary using bytetobin function below , convert hex using bintohex1 . feel stupid , works slow. know how can directly results without 2 conversions? thanks!! here codes: procedure tform1.idudpserver1udpread(athread: tidudplistenerthread; const adata: tidbytes; abinding: tidsockethandle); var buf: tidbytes; buffer: string; data_received: string; begin if bytestostring(adata) <> 'hello' begin buffer := hextostring('00'); setlength(buf, length(buffer)); copytidstring(buffer, buf, 0); abinding.sendto(abinding.peerip, abinding.peerport, buf); data_received := bintohex1(bytetobin(adata[1]) + bytetobin(adata[2]) + bytetobin(adata[3]) + bytetobin(adata[4]) + bytetobin(adata[5]) + bytetobin(adata[6]) + bytetobin(adata[7]) + bytetobin(adata[8]) + bytetobin(adata[9]) + bytetobin(adata[10]) + bytetobin(adata[11...
Read more

javascript - Any ideas when Firefox is likely to implement lengthAdjust and textLength? -

-
any ideas when firefox implement lengthadjust andtextlength?..... working svg application. lengthadjust , textlength working fine in chrome not working in fire fox . <svg viewbox = "0 0 500 300" version = "1.1"> <defs> <path id="s3" d="m 10,90 q 100,15 200,70" /> </defs> <g> <text font-size = "20"> <textpath xlink:href="#s3" textlength="205"> short text</textpath> </text> <use xlink:href="#s3" fill="none" stroke="black" stroke-width="1"/> </g> </svg> this implemented in firefox text elements (not textpath or tspan) in case that's ok though can move attribute text element. <svg viewbox = "0 0 500 300" version = "1.1"> <defs> ...
Read more