[R sqlite的：兩個表的更新提供了語法錯誤， 「近」「：

Question

我願做一個UPDATE與SQLite的兩個表

x1 <- data.frame(id = rep(1,3), 
        t = as.Date(c("2000-01-01","2000-01-15","2000-01-31")) 
) 
x1.h <- 0 
x2 <- data.frame(id = 1, start = as.Date("2000-01-14")) 

更新爲：

sqldf(paste("UPDATE x1" 
     ," SET x1.h = 1" 
     ," WHERE EXISTS (SELECT *" 
     ,"    FROM x2" 
     ,"    WHERE x1.id = x2.id" 
     ,"      AND x1.t < x2.start" 
     ,"    )" 
     ) 
) 

我得到以下錯誤：？

Error in sqliteExecStatement(con, statement, bind.data) : 
    RS-DBI driver: (error in statement: near ".": syntax error) 

有別人的想法有什麼不順心 感謝幫助

Answer 1

我認爲你的內在SELECT沒有說它從哪裏選擇。單獨嘗試。我認爲它應該看起來更像：

SELECT * FROM x1,x2 WHERE x1.id = x2.id AND x1.t < x2.start 

Answer 2

爲什麼你用sqldf更新？我認爲sqldf是ONy select聲明。

我會用RSQLite這個。

首先我糾正你的sql statetemnt。我更喜歡使用九月 '\ n'，要獲得相當的要求與貓

str.update <- paste(" UPDATE x1" 
      ," SET h = 1 "    ## here the error 
      ," WHERE EXISTS (SELECT * " 
      ,"    FROM x2 "    ## here second error 
      ,"    WHERE x1.id = x2.id " 
      ,"    AND x1.t < x2.start " 
      ,"  )" 
     ,sep ='\n' 
) 


cat(str.update) 
UPDATE x1 
SET h = 1 
WHERE EXISTS (SELECT * 
       FROM x1,x2 ## 
       WHERE x1.id = x2.id 
       AND x1.t < x2.start 
     ) 

然後，你可以這樣做：

library(RSQLite) 
con <- dbConnect(SQLite(), ":memory:") 
dbWriteTable(con, "x1", x1)   # I create my table x1 
dbWriteTable(con, "x2", x2)   # I create my table x2 
res <- dbSendQuery(con, str.update) 
dbReadTable(con,name='x1')   ## to see the result 

編輯

我歐普澄清後編輯我的答案（ FROM x1,x2變成FROM x2）

Answer 3

我發現這個解決方案：

x1$h <- 0 
x1 <- sqldf(c("UPDATE x1 
     SET h = 1 
     WHERE EXISTS (SELECT x1.id 
         FROM x2 
         WHERE x1.id = x2.id 
          AND x1.t < x2.start 
        )", 
     "SELECT * FROM main.x1")) 

，並提供：

> x1 

    id   t h 
1 1 2000-01-01 1 
2 1 2000-01-15 0 
3 1 2000-01-31 0 

來源： https://code.google.com/p/sqldf/#8._Why_am_I_having_problems_with_update？ 其他要提醒的事情：顯然別名不起作用，例如UPDATE x1 a ... 感謝您的幫助。