R數據庫提取限制問題

Question

我是一個初學者到R和我不知道我的標題是否合適的問題，我有一個問題，從R中的SQL提取一些數據，這是代碼

> flights = select(paste("SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT", 1000)) 

> flights = select(paste("SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT", 10000)) 

> flights = select(paste("SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT", 100000)) 
Error in .local(conn, statement, ...) : 
could not run statement: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1e+05' at line 1 
Called from: eval(substitute(browser(skipCalls = pos), list(pos = 9 - frame)), 
envir = sys.frame(frame)) 

> flights = select(paste("SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT", 1000000)) 
Error in .local(conn, statement, ...) : 
could not run statement: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1e+06' at line 1 
Called from: eval(substitute(browser(skipCalls = pos), list(pos = 9 - frame)), 
envir = sys.frame(frame)) 

> flights = select(paste("SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT", 1000001)) 

> flights = select(paste("SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT", 100000001)) 

所以這裏是我的疑問，當限制小於10000或最多4個零沒有錯誤，但約5或更多的零拋出錯誤。但如果限制以0以外的數字結束，那麼沒有錯誤，爲什麼？

而且選擇功能提前

select <- function (query, connection=con) { 
return(as.data.frame(dbGetQuery(connection, query))) 
} 

感謝

Answer 1

的大數字轉換爲科學記數法，您可以運行options(scipen=999)，以防止這種情況：

options(scipen=999) 
paste("SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT", 1000000) 
# "SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT 1000000" 

要恢復它，運行options(scipen=0)：

options(scipen=0) 
paste("SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT", 1000000) 
#"SELECT DISTINCT flight FROM messages ORDER BY id DESC LIMIT 1e+06"