Is there a “the item before this item in the BTREE index” operator?









up vote
0
down vote

favorite












I need to update a record matching a secondary key where a certain timestamp field is the highest value under a certain other value. I have a composite BTREE index that covers the two relevant columns.



Is there an equivalent of Java's TreeMap.floorKey() to retrieve the corresponding value in a PostgreSQL index?



I tried Googling for a solution and found only convoluted work-arounds for what should be a very simple and specific operation.






postgresql







share|improve this question





















  • Maybe a combination of ORDER BY, LIMIT, and OFFSET. Otherwise post more details.
    – eurotrash
    Nov 10 at 22:10














up vote
0
down vote

favorite












I need to update a record matching a secondary key where a certain timestamp field is the highest value under a certain other value. I have a composite BTREE index that covers the two relevant columns.



Is there an equivalent of Java's TreeMap.floorKey() to retrieve the corresponding value in a PostgreSQL index?



I tried Googling for a solution and found only convoluted work-arounds for what should be a very simple and specific operation.






postgresql







share|improve this question





















  • Maybe a combination of ORDER BY, LIMIT, and OFFSET. Otherwise post more details.
    – eurotrash
    Nov 10 at 22:10












up vote
0
down vote

favorite









up vote
0
down vote

favorite











I need to update a record matching a secondary key where a certain timestamp field is the highest value under a certain other value. I have a composite BTREE index that covers the two relevant columns.



Is there an equivalent of Java's TreeMap.floorKey() to retrieve the corresponding value in a PostgreSQL index?



I tried Googling for a solution and found only convoluted work-arounds for what should be a very simple and specific operation.






postgresql







share|improve this question













I need to update a record matching a secondary key where a certain timestamp field is the highest value under a certain other value. I have a composite BTREE index that covers the two relevant columns.



Is there an equivalent of Java's TreeMap.floorKey() to retrieve the corresponding value in a PostgreSQL index?



I tried Googling for a solution and found only convoluted work-arounds for what should be a very simple and specific operation.






postgresql




postgresql






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 10 at 21:50









Alex R

4,03294796




4,03294796











  • Maybe a combination of ORDER BY, LIMIT, and OFFSET. Otherwise post more details.
    – eurotrash
    Nov 10 at 22:10
















  • Maybe a combination of ORDER BY, LIMIT, and OFFSET. Otherwise post more details.
    – eurotrash
    Nov 10 at 22:10















Maybe a combination of ORDER BY, LIMIT, and OFFSET. Otherwise post more details.
– eurotrash
Nov 10 at 22:10




Maybe a combination of ORDER BY, LIMIT, and OFFSET. Otherwise post more details.
– eurotrash
Nov 10 at 22:10

















active

oldest

votes











Your Answer






StackExchange.ifUsing("editor", function ()
StackExchange.using("externalEditor", function ()
StackExchange.using("snippets", function ()
StackExchange.snippets.init();
);
);
, "code-snippets");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "1"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);













 

draft saved


draft discarded


















StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53243754%2fis-there-a-the-item-before-this-item-in-the-btree-index-operator%23new-answer', 'question_page');

);

Post as a guest















Required, but never shown






























active

oldest

votes













active

oldest

votes









active

oldest

votes






active

oldest

votes















 

draft saved


draft discarded















































 


draft saved


draft discarded














StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53243754%2fis-there-a-the-item-before-this-item-in-the-btree-index-operator%23new-answer', 'question_page');

);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







-

這個網誌中的熱門文章

How to read a connectionString WITH PROVIDER in .NET Core?

圖片
6 I added .AddJsonFile("Connections.json", optional: true, reloadOnChange: true) in public Startup(IHostingEnvironment env) Connections.json contains: "ConnectionStrings": "DefaultConnection": "Server=(localdb)\mssqllocaldb;Database=DATABASE;Trusted_Connection=True;MultipleActiveResultSets=true", "COR-W81-101": "Data Source=DATASOURCE;Initial Catalog=P61_CAFM_Basic;User Id=USERID;Password=PASSWORD;Persist Security Info=False;MultipleActiveResultSets=False;Packet Size=4096;", "COR-W81-100": "Data Source=DATASOURCE;Initial Catalog=Post_PS;User Id=USERID;Password=PASSWORD;Persist Security Info=False;MultipleActiveResultSets=False;Packet Size=4096;", "MSEDGEWIN10": "Data Source=DATASOURCE; Initial Catalog=COR_Basic; Persist Security Info=False;Integrated Security=true;MultipleActiveResultSets=False;Packet Size=4096;Application Name="COR_Basic"", "server&qu
閱讀完整內容

In R, how to develop a multiplot heatmap.2 figure showing key labels successfully

圖片
1 2 I'm trying to develop a multiplot heatmap.2 saved to a pdf. I'm having some success but the axis labels are getting chopped off. Subplot titles are also desirable but again the labels are getting chopped. Here's my reproducible code: library(gridExtra) library(grid) library(gridGraphics) library(gplots) Col = colorRampPalette(c("red","orange","yellow", "white")) grab_grob <- function() grid.echo() grid.grab() par(cex.main=0.1, mar = c(1,1,1,1) ) #data<-read.table("heatmap.input.matrix.data.txt") lmat = rbind(c(2,3),c(4,1),c(4,1)) lwid = c(2.5,4) lhei = c(0.5,4,3) labRowvec <- c(rep(NULL, dim(matrix(runif(1000, 1,10),ncol=50))[1])) labColvec <- c(rep(NULL, dim(matrix(runif(1000, 1,10),ncol=50))[2])) gl <- lapply(1:12, function(i) heatmap.2(matrix(runif(1000, 1,10),ncol=50), dendrogram = "none",offsetRow=-0.5, offsetCol=-1,srtCol=0, density="density", lmat =lmat,lhei = l
閱讀完整內容

Museum of Modern and Contemporary Art of Trento and Rovereto

圖片
Art museum in Rovereto TN, Italy Museum of Modern and Contemporary Art of Trento and Rovereto Museo d'arte moderna e contemporanea di Trento e Rovereto MART, Entrance Location Corso Angelo Bettini, 43, 38068 Rovereto TN, Italy Coordinates 45°53′38″N 11°02′42″E  /  45.8940°N 11.0450°E  / 45.8940; 11.0450 Coordinates: 45°53′38″N 11°02′42″E  /  45.8940°N 11.0450°E  / 45.8940; 11.0450 Type Art museum Director Gianfranco Maraniello Public transit access Trento train station. Taxis outside station. Website mart.trento.it The Museum of Modern and Contemporary Art of Trento and Rovereto (MART) ( Museo d'Arte Moderna e Contemporanea di Trento e Rovereto , in Italian) is a museum centre in the Italian province of Trento. The main site is in Rovereto, and contains mostly modern and contemporary artworks, including works from renowned Giorgio Morandi, Giorgio de Chirico, Felice Casorati, Carlo Carrà and Fortunato Depero. Fortunato Depero's house in Rovereto (known as Casa d
閱讀完整內容