R数据库提取限制问题

Question

我是一个初学者到R和我不知道我的标题是否合适的问题，我有一个问题，从R中的SQL提取一些数据，这是代码

> 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)) 

所以这里是我的疑问，当限制小于10000或最多4个零没有错误，但约5或更多的零抛出错误。但如果限制以0以外的数字结束，那么没有错误，为什么？

而且选择功能提前

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

感谢

Answer 1

的大数字转换为科学记数法，您可以运行options(scipen=999)，以防止这种情况：

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" 

要恢复它，运行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"