R has a package calledsqldfthat allows developers to manipulate data inside a dataframe in the same way a SQL developer, queries a SQL table. In this tutorial I will show how to install the package and how to use it to query some values from the sample AdventureWorks2014 database. Step 1...
1 Can't figure out why syntax error near "from" is appearing for sqldf in R 5 Error in R Using SQLDF: too many SQL variables 2 Error running a SQL query in R with sqldf 0 sqldf() fails with "could not find function "sqldf" error 1 Sqldf in R - error with first column ...
a10r <- head(warpbreaks[order(warpbreaks$breaks, decreasing = TRUE), ], 3) a10s <- sqldf("select * from warpbreaks order by breaks desc limit 3") row.names(a10r) <- NULL identical(a10r, a10s)
> sqldf("SELECT * FROM data + WHERE am = 1 AND cyl in (6,8) + ORDER BY hp DESC") mpg cyl disp hp am 1 15.0 8 301 335 1 2 15.8 8 351 264 1 3 19.7 6 145 175 1 4 21.0 6 160 110 1 5 21.0 6 160 110 1 # 添加观测(纵向合并数据集) R :rbind(数据集A, 数据集B) S...
I'm trying to rewrite some code using the sqldf library in R, which should allow me to run SQL queries on data frames, but I am having an issue in that whenever I try to run a query, R seems like it tries to query the actual real MySQL db con that I use and look for a table...
熟悉MySQL的朋友可以使用sqldf来操作数据框 #引入sqldf库(sqldf)library(sqldf)#释放RMySQL库的加载(针对sqldf报错)#detach("package:RMySQL", unload=T)#读取数据data <- read.csv("data.csv")#sql查询results <- sqldf("select distinct(name) from data")#获取故障代码列表,R中for循环不能处理List,需要转换...
for (r in 2:nrow(dates_df)){ ##连续周数 if (dates_df$wday[r] == 1){##如果是周日, 周数加1 wnum_conti <- wnum_conti + 1 } wnums_conti <- c(wnums_conti, wnum_conti) dates_df$wnum_conti <- wnums_conti df <- sqldf('select dates_df.*, df.dnum from ...
casewhenresultado_operacionin('EXITO','CORRECTO') then'EXITO' else'SINEXITO' endasRESULTADO_ACTUAL from verif_obligaleftjoinfin2016b on a.CUPS=b.CUPS_Largoanda.DIVISION=b.DIVISION") 有人可以帮我找到这个解决方案吗? 非常感谢你 看答案
解决;R语言使用sqldf库是报错"Failed to connect to database: Error: Access denied for user '..'@'localhost' (using password: NO) Error in !dbPreExists : invalid argument type" 原因:在使用sqldf时,不需要加载RMySQL库 解决方案:在控制台执行释放RMySQL库加载...
通过sqldf包,可直接在R中的数据框(data.frame)(类似数据库中的表)上进行SQL操作,R中数据清洗常用的dplyr包的许多函数操作也是将相应的命令转化为SQL语句来执行。sqldf包支持SQLite(默认), H2,MySQL及PostgreSQL作为后台来执行SQL语句。SQLite及H2是两个无服务器端,无需配置的轻量级数据库管理系统,在R中安装好并加载...